ICSE Class 10 Mathematics

ICSE MATHEMATICS FORMULAS and INFORMATION

There will be one paper of \(2\frac{1}{2}\) hours duration carrying 80 marks and Internal Assessment of 20 marks.

The paper will be divided into **two** Sections. Section I (40 marks), Section II (40 marks).

Section I: It will consist of compulsory short answer questions.

Section II: Candidates will be required to answer **four** out of **seven** questions.

UNITS & CHAPTERS

1. COMMERCIAL ARITHMETIC

• Compound Interest (Paying back in equal installments not included)
• Sales Tax and Value Added Tax
• Banking (Saving Bank Accounts and Recurring Deposit Accounts)
• Shares and Dividends (Brokerage and fractional shares not included)

2. ALGEBRA

• Linear Inequations
• Quadratic Equations and Solving Problems
• Ratio and Proportion
• Remainder and Factor Theorems (f(x) not to exceed degree 3)
• Matrices

3. CO-ORDINATE GEOMETRY

• Reflection
• Distance and Section Formulae
• Equation of a Straight Line

4. GEOMETRY

• Symmetry
• Similarity
• Loci (Locus and Its Constructions)
• Circles
• Tangents and Intersecting Chords
• Constructions (tangents to circle, circumscribing & inscribing circle on ∆ & reg. hexagon)

5. MENSURATION

• Circumference and Area of a circle (Area of sectors of circles other than semi-circle and quarter-circle not included)
• Surface Area and Volume (of solids)

6. TRIGONOMETRY

• Trigonometrical Identities and Trigonometrical Tables
• Heights and Distances (Cases involving more than 2 right angled As excluded)

7. STATISTICS

• Graphical Representation (Histogram and Ogives)
• Measures of Central Tendency (Mean, Median, Quartiles and Mode)
• Probability

COMMERCIAL ARITHMETIC

Compound Interest:

• A = P + I
• S.I. \( = \frac{P \times R \times T}{100} \)
• S.I. for 1\(^{st}\) year = C.I. for 1\(^{st}\) year
• C. I. for (n + 1) year = C.I. of n\(^{th}\) year + Int. on it for 1 year ; R% \( = \frac{(C_2-C_1) \times 100}{C_1}\) %, where T = 1yr
• Amount in (n + 1) year = Amount in n\(^{th}\) year + Int. on it for 1 year; R% \( = \frac{(A_2-A_1) \times 100}{A_1}\) %
• \( A = P (1 + \frac{r}{100})^n \)
• \( C.I. = P [(1+\frac{r}{100})^n - 1] \)
• \( A = P (1+\frac{r_1}{100})(1+\frac{r_2}{100}) (1 + \frac{r_3}{100}) \); when rates for successive years are different.
• \( A = P (1 + \frac{r}{2 \times 100})^{n \times 2} \); when the interest is compounded half-yearly.
• \( A = P (1+\frac{r}{100})^2 (1 + \frac{r}{2 \times 100})^1 \), If the time is \(2\frac{1}{2}\) years and the rate is compounded yearly.
• For Growth: V = V\(_{0}\) \( (1 + \frac{r}{100})^n \), V\(_{0}\) = Initial Value, V = Final Value
• For Depreciation: V = V\(_{0}\) \( (1 - \frac{r}{100})^n \)

Sales Tax and Value Added Tax:

• The price at which an Article is marked : List Price/Marked Price/Printed Price/Quoted Price
• Sale Price = M.P. - Discount, Discount is calculated on M.P.
• Sales Tax is calculated after deducting the discount (on the discounted price).
• Sales Tax \( = \frac{\text{Rate of Sales Tax} \times \text{Sales Price}}{100} \)
• Sale-price \( = (\frac{100+\text{Profit%}}{100}) \times C.P. \)
• Sale-price \( = (\frac{100-\text{Loss%}}{100}) \times C.P. \)
• Sale-price \( = (\frac{100-\text{discount%}}{100}) \times M.P. \)
• VAT paid by a person \( = \frac{\text{price Added by the person} \times \text{VAT%}}{100} \)
• VAT = Tax recovered(charged) on the sale - Tax paid on the purchase

Banking:

1. SB Account:

a. Withdrawal = Debit
b. Deposit = Credit
c. Steps for calculation of interest:
(i) Find the minimum balance of each month between 10\(^{th}\) day and the last day.
(ii) Add all the balances. This is the Equivalent Monthly Principal for 1 month.
(iii) Calculate the SI on the Equivalent Monthly Principal with T \( = \frac{1}{12} \) years.
(iv) No interest is paid for the month in which the account is closed.
(v) If the Amount Received on closing is asked, add the interest to the LAST BALANCE and not to the Equivalent Monthly Principal.

2. RD Account:

a. \( I = \frac{P \times n(n+1) \times r}{2 \times 12 \times 100} \); \( T = \frac{n(n+1)}{2 \times 12} \) years ; P = monthly deposit, n = no. of months, r = rate%
b. M.V. = P \(\times\) n + I ; Maturity Value = Total deposit (monthly deposit \(\times\) n) + Interest

Shares and Dividend:

• The total money invested by the company is called its capital stock.
• The capital stock is divided into a number of equal units. Each unit is a called a share.
• Nominal Value is also called Register Value, Printed Value, and Face Value.
• The FV of a share always remains the same, while its MV goes on changing.
• The part of the profit of a company which is distributed amongst the shareholders is known as dividend.
• If the MV of the share is same as its NV, the share is said to be at par.
• If the MV of the share is greater than NV, the share is said to be at premium.
• If the MV of the share is less than NV, the share is said to be at discount.
• No. of shares \( = \frac{\text{Investment}}{\text{MV of each share}} \)
• Dividend = Rate of Dividend \(\times\) NV \(\times\) No. of shares ; total annual income = DNN or DFN
• Return % \( = \frac{\text{Dividend}}{\text{Investment}} \times 100\% \)
• Rate of dividend% \(\times\) NV = Return % \(\times\) MV ; DN = PM
• % increase in return on original investment \( = \frac{\text{New Dividend}}{\text{Original Investment}} \times 100\% \)
• % increase in return \( = \frac{\text{New Dividend-Old Dividend}}{\text{Old dividend}} \times 100\% \)

ALGEBRA

Linear Inequations:

• The signs >, <, \(\geq\) and \(\leq\) are called signs of inequality.
• On transferring +ve term becomes -ve and vice versa.
• If each term is multiplied or divided by +ve number, the sign of inequality remains the same.
• The sign of inequality reverses:

If each term is multiplied or divided by same negative number.
If the sign of each term on both the sides of an inequation is changed.
On taking reciprocals of both sides, in case both the sides are positive or negative.

• Always, write the solution set for the inequation, e.g., {x : x\(\leq\)3, x \(\in\) N}, solution set = {1, 2, 3}
• To represent the solution on a number line:

Put arrow sign on both the ends of the line and keep extra integers beyond the range.
Use dark dots on the line for each element of N, W and Z.
For Q, R: mark range with solid circle \( \bullet \) (for \(\geq\) or \(\leq\)), hollow circle \( \circ \) (for < and >.)

• "and" means Intersection ( only common elements of the sets).
• "or" means Union(all elements of the sets without repetition).

Quadratic Equations:

1. Quadratic equation is an equation with one variable, the highest power of the variable is 2.

2. Some useful results:
a) \( (a + b)^2 = a^2 + b^2 + 2ab \)
b) \( (a - b)^2 = a^2 + b^2 - 2ab \)
c) \( a^2-b^2= (a + b) (a - b) \)
d) \( (a + b)^2 - (a - b)^2 = 4ab \)
e) \( (a + b)^3 = a^3 + b^3 + 3ab(a + b) \)
f) \( (a - b)^3 = a^3 - b^3 - 3ab(a - b) \)

g) \( (a + b + c)^2 = a^2 + b^2 + c^2 + 2ab + 2bc + 2ca \)
h) \( a^3 + b^3 + c^3 - 3abc = (a + b + c) (a^2 + b^2 + c^2 - ab - bc - ca) \)

3. Steps for solving quadratic equation by factorization:
a. Clear all fractions and brackets if necessary.
b. Bring it to the form \( ax^2 + bx + c = 0 \) by transposing terms.
c. Factorize the expression by splitting the middle term as a sum of product of a and c.

4. Discriminant (D) \( = b^2 - 4ac \)
a. if D > 0, then the roots are real and unequal
b. if D = 0, then the roots are real and equal
c. if D < 0, then the roots are not real (imaginary).

5. The roots of the quadratic equation \( ax^2 + bx + c = 0 ; a \neq 0 \) can be obtained by using the formula:
\[ X = \frac{-b \pm \sqrt{b^2-4ac}}{2a} \]

Ratio and Proportion:

• A ratio is a comparison of the sizes of two or more quantities of the same kind by division. Since ratio is a number, so it has no units.
• To find the ratio between two quantities, change them to the same units.
• To compare two ratios, convert them into like fractions.
• In the ratio, a : b, a is called antecedent and b is called consequent.
• \( \frac{a}{b} = \frac{c}{d} \implies \frac{a+c+e}{b+d+f} \)
• Compound ratio of a : b and c : d is \( (a \times c) : (b \times d) \)
• Duplicate ratio of a : b is \( a^2 : b^2 \)
• Triplicate ratio of a : b is \( a^3 : b^3 \)
• Sub-duplicate ratio of a : b is \( \sqrt{a} : \sqrt{b} \)

• Sub-triplicate ratio of a : b is \( \sqrt[3]{a} : \sqrt[3]{b} \)
• Reciprocal ratio of a : b is b : a
• Proportion- An equality of two ratios is called a proportion. Written as: a :b::c:d or \( \frac{a}{b} = \frac{c}{d} \)
• Product of extreme terms = product of middle terms, if a, b, c, d are in proportion then ad = bc
• Continued Proportion- a : b :: b : c or a : b = b : c ; mean proportion (b) = \( \sqrt{ac} \)
• Invertendo - If a : b = c : d, then b : a = d : c
• Alternendo - If a : b = c : d, then a : c = b : d
• Componendo - If a : b = c : d, then a + b : b = c + d : d
• Dividendo - If a : b = c : d, then a - b : b = c - d : d
• Componendo and Dividendo - If a : b = c : d, then a + b : a - b = c + d : c-d

Remainder and Factor Theorem:

1. If f (x) is a polynomial, which is divisible by (x - a), a \(\in\) R, then the remainder is f (a).

2. If the remainder on dividing a polynomial f (x) by (x - a), f (a) = 0, then (x - a) is a factor of f (x).

3. When f(x) is divided by (ax + b), then remainder is \( f(-\frac{b}{a}) \), a \(\neq\) 0

4. When f(x) is divided by (ax - b), then remainder is \( f(\frac{b}{a}) \), a \(\neq\) 0

Matrices:

• A rectangular arrangement of numbers, in the form of horizontal (rows) and vertical lines (columns) is called a matrix. Each number of a matrix is called its element. The elements of a matrix are enclosed in brackets [ ].
• The order of a matrix = No. of rows \(\times\) No. of columns
• Row matrix: Only 1 row. \[a \quad b\]
• Column matrix: Only 1 column. \( \begin{bmatrix} a \\ b \end{bmatrix} \)

• Square matrix: No. of rows = No. of columns. \( \begin{bmatrix} a & b & c \\ d & e & f \\ g & h & i \end{bmatrix} \)
• Rectangular matrix: No. of rows \(\neq\) No. of columns. \( \begin{bmatrix} a & b \\ c & d \\ e & f \end{bmatrix} \)
• Zero matrix: All elements are zero. \( \begin{bmatrix} 0 & 0 & 0 \\ 0 & 0 & 0 \end{bmatrix} \)
• Diagonal matrix: A square matrix with all the elements zero except the elements on the leading diagonal. \( \begin{bmatrix} a & 0 & 0 \\ 0 & b & 0 \\ 0 & 0 & c \end{bmatrix} \)
• Unit matrix (I): A diagonal matrix with all the elements on the leading diagonal = 1; I \( = \begin{bmatrix} 1 & 0 \\ 0 & 1 \end{bmatrix} \)
• Transpose of a matrix: If A \( = \begin{bmatrix} 1 & 2 & 5 \\ 2 & 3 & 6 \end{bmatrix} \) then A\(^{T}\) \( = \begin{bmatrix} 1 & 2 \\ 2 & 3 \\ 5 & 6 \end{bmatrix} \)
• Addition or subtraction of matrices is possible iff they are of the same order.
• Addition of two matrices: \( \begin{bmatrix} a & b \\ c & d \end{bmatrix} + \begin{bmatrix} k & l \\ m & n \end{bmatrix} = \begin{bmatrix} a+k & b+l \\ c+m & d+n \end{bmatrix} \)
• Multiplication of matrix by a real number: \( i \times \begin{bmatrix} a & b \\ c & d \end{bmatrix} = \begin{bmatrix} a \times i & b \times i \\ c \times i & d \times i \end{bmatrix} \)
• Multiplication of 2 matrices: \( \begin{bmatrix} a & b \\ c & d \end{bmatrix} \times \begin{bmatrix} p & q \\ r & s \end{bmatrix} = \begin{bmatrix} a \times p + b \times r & a \times q + b \times s \\ c \times p + d \times r & c \times q + d \times s \end{bmatrix} \), order of the product matrix = (x \(\times\) a), Multiplication process. \( \begin{bmatrix} a & b \\ c & d \end{bmatrix} \begin{bmatrix} p & q \\ r & s \end{bmatrix} = \begin{bmatrix} ap+br & aq+bs \\ cp+dr & cq+ds \end{bmatrix} \), run & fall

COORDINATE GEOMETRY

Reflection:

• M\(_{x}\) (x, y) = (x, -y)
• M\(_{y}\) (x, y) = (-x, y)
• M\(_{o}\) (x, y) = (-x, -y)
• X- axis: y = 0
• Y- axis: x = 0
• Any point that remains unaltered under a given transformation is called an invariant point.
• (x, y) \( \xrightarrow{\text{under x = a}} \) (2a - x, y )
• (x, y) \( \xrightarrow{\text{under y = a}} \) (x, 2a - y)

More Coordinate Geometry:

• Distance formula: Distance between 2 given points (x\(_{1}\), y\(_{1}\)) and (x\(_{2}\), y\(_{2}\)) \( = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} \)
• Distance between the origin (0, 0) and any point (x, y) \( = \sqrt{(x)^2 + (y)^2} \)
• To show the quadrilateral as a parallelogram or rhombus, find all four sides.
• To show the quadrilateral as a rectangle or square, find all four sides and both the diagonals.
• Section formula: Coordinates of a point P(x, y) \( = (\frac{m_1x_2 + m_2x_1}{m_1 + m_2}, \frac{m_1y_2 + m_2y_1}{m_1 + m_2}) \) ; ratio = m\(_{1}\) : m\(_{2}\)
• Midpoint formula: Coordinates of the midpoint M(x, y) of a line segment \( = (\frac{x_1+x_2}{2}, \frac{y_1+y_2}{2}) \)
• The co-ordinates of the centroid of a triangle G(x, y) \( = (\frac{x_1+x_2+x_3}{3}, \frac{y_1+y_2+y_3}{3}) \)

Equation of a Line:

• Every straight line can be represented by a linear equation.
• Any point, which satisfies the equation of a line, lies on that line.

• Inclination of a line is the angle \(\theta\) which the part of the line makes with x-axis.
• Inclination \(\theta\) is positive in anti-clockwise direction and negative in clockwise direction.
• Slope or gradient of any inclined plane is ratio of vertical rise and horizontal distane.
• Slope of a line (m) \( = \frac{\text{vertical rise}}{\text{horizontal distance}} = \tan\theta \)
• Inclination \(\theta\) of x-axis and every line parallel to it is 0\(^{\circ}\).
• Inclination \(\theta\) of y-axis and every line parallel to it is 90\(^{\circ}\).
• Slope of a line which passes through any two points P(x\(_{1}\), y\(_{1}\)) and Q(x\(_{2}\), y\(_{2}\)) \( = (\frac{y_2-y_1}{x_2-x_1}) \)
• Slopes of two parallel lines are equal or m\(_{1}\) = m\(_{2}\).
• Product of the slopes of two perpendicular line = -1 or m\(_{1}\) x m\(_{2}\) = -1.
• Equation of a line:
  \( \circ \) y = mx + c : (Slope-intercept form : m = slope, c = y-intercept)
  \( \circ \) (y-y\(_{1}\)) = m(x - x\(_{1}\)) : (Slope-point form : (x\(_{1}\), y\(_{1}\)) = co-ordinates of the point)
  \( \circ \) (y-y\(_{1}\)) = m(x - x\(_{1}\)) : (Two point form - where \( m = \frac{y_2-y_1}{x_2-x_1} \)).

GEOMETRY

Symmetry:

• A figure is said to have line symmetry if on folding the figure about this line, the two parts of the figure exactly coincide.

Similarity:

• Criteria for similarity - 1. AA or AAA
  2. SAS
  3. SSS
• A \(\perp\)drawn from vertex of a rt-zd \(\Delta\) divides the \(\Delta\) into 2 similar\(\Delta\)s, also to original triangle.
• BPT - A line drawn || to any side of a \(\Delta\) divides other two sides proportionally.
• The areas of 2 similar \(\Delta\)s are proportional to the square of their corresponding sides.
• Median divides a triangle into 2\(\Delta\)s of equal area.
• If \(\Delta\)s have common vertex & are between same ||, ratio of their areas = ratio of bases.
• Scale factor = k, k \( = \frac{\text{length of model}}{\text{length of object}} \) ; k\(^2 = \frac{\text{area of model}}{\text{area of object}} \) ; k\(^3 = \frac{\text{volume of model}}{\text{volume of object}} \)

Loci:

• The locus is the set of all points which satisfy the given geometrical condition.
• Locus of a point equidistant from 2 fixed points is \(\perp\) bisector of line segment joining them.
• Locus of a point equidistant from 2 intersecting lines is angle bisector between the lines.
• Locus of a point at a constant distance from a fixed point is circle.
• Locus of a point equidistant from a given line is a pair of lines parallel to the given line and at the given distance from it.
• For equilateral triangle, centroid = incentre = circumcentre = orthocentre

Circle:

• A line drawn from centre of a circle to bisect the chord is \(\perp\) to the chord.
• A perpendicular line drawn to a chord from the centre of the circle bisects the chord.
• The \(\perp\) bisector of a chord passes through the centre of the circle.
• One and only one circle can be drawn passing through 3 non-collinear points.
• Equal chords are equidistant from the centre.

• Chords which are equidistant from the centre are equal in length.
• If the parallel chords are drawn in a circle, then the line through the midpoints of the chords passes through the centre.
• Greater the size of chord, lesser is its distance from the centre.
• Angle at the centre = 2 \(\times\) angle on the circumference.
• Angles in the same segment are equal.
• Angle in a semicircle is a right angle.
• The opposite angles of a cyclic quadrilateral are supplementary.
• If the opposite angles of a quadrilateral are supplementary, then the quadrilateral is cyclic.
• Angle in the major segment is acute and in the minor segment is obtuse.
• Exterior angle of a cyclic quadrilateral = Interior opposite angle.
• In equal or same circle. If two arcs subtend equal angle at the centre, then they are equal.
• In equal circle, if two arcs are equal, then they subtend equal angle at the centre.
• In equal circle, if two chords are equal, they cut off equal arcs.
• In equal circle, if two arcs are equal, the chords of the arcs are also equal.
• The tangent at any point of a circle & the radius through this point are \(\perp\) to each other.
• If two tangents are drawn to a circle from an exterior point,
  \( \circ \) The tangents are equal,
  \( \circ \) They subtend equal angle at the centre of the circle,
  \( \circ \) They are equally inclined to the line joining the point and the centre of the circle.
• If two chords of a circle intersect internally/externally, the product of their segments is equal.
• Angle in the alternate segment are equal.
• Tangent\(^2\) = product of the lengths of the segments of the chord.
• Incentre - Point of intersection of the angle bisectors.
• Cicumcentre - Point of intersection of the \(\perp\) bisectors of the sides.

MENSURATION

Circumference and Area of a Circle:

• Circumference of a circle = \(2\pi r\)
• Circumference of a semi-circle = \( \pi r + 2r \)
• Circumference of a quarter-circle = \( \frac{1}{2}\pi r + 2r \)
• Area of a circle = \( \pi r^2 \)
• Area of a circular ring = \( \pi (R^2 - r^2) \)
• Area of a semi-circle = \( \frac{1}{2}\pi r^2 \)
• Area of a quarter-circle = \( \frac{1}{4}\pi r^2 \)
• Distance travelled by a wheel in one revolution = Its circumference
• No. of Revolutions \( = \frac{\text{Total distance travelled}}{\text{Circumference of the wheel}} \)
• Area of a triangle \( = \frac{1}{2} \times b \times h \)
• Area of scalene triangle \( = \sqrt{s(s-a)(s-b)(s-c)} \), \( s = \frac{a+b+c}{2} \)
• Area of equilateral triangle \( = \frac{\sqrt{3}}{4} a^2 \)

Surface Area and Volume:

• Volume of a cuboid = \( l \times b \times h \)
• Area of 4 walls of a cuboid = \( 2(l + b) \times h \)
• T.S.A. of a cuboid = \( 2(lb + bh + hl) \)
• Diagonal a cuboid \( = \sqrt{l^2 + b^2 + h^2} \)
• Volume of a cube = \( a^3 \)

Trigonometry

Trigonometry:

Statistics

Statistics:

Probability

Probability:

• Area of 4 walls of a cube = \( 4a^2 \)
• T.S.A. of a cube = \( 6a^2 \)
• Diagonal of a cube = \( a\sqrt{3} \)
• Volume of a solid cylinder = \( \pi r^2h \)
• C.S.A. of a solid cylinder = \( 2\pi rh \)
• T.S.A. of a solid cylinder = \( 2\pi r(h + r) \)
• Volume of a hollow cylinder = \( \pi (R^2 - r^2)h \)
• T.S.A. of a hollow cylinder = \( 2\pi rh + 2\pi Rh + 2\pi (R^2 - r^2) \)
• Slant height of a right circular cone, \( l = \sqrt{h^2 + r^2} \)
• Volume a right circular cone \( = \frac{1}{3}\pi r^2h \)
• C.S.A. of a right circular cone \( = \pi rl \)
• T.S.A. of a right circular cone = \( \pi r(l + r) \)
• Volume a sphere \( = \frac{4}{3}\pi r^3 \)
• Surface area a sphere = \( 4\pi r^2 \)
• Volume a hemisphere \( = \frac{2}{3}\pi r^3 \)
• Curved Surface area a hemisphere = \( 2\pi r^2 \)
• Total Surface area a hemisphere = \( 3\pi r^2 \)
• Volume a hollow sphere = \( \frac{4}{3}\pi (R^3 - r^3) \)
  • PBP OR HHB OAO HHA
    \( \sin \theta = \frac{P}{H} \) | \( \cos \theta = \frac{B}{H} \) | \( \tan \theta = \frac{P}{B} \)
    \( \csc \theta = \frac{H}{P} \) | \( \sec \theta = \frac{H}{B} \) | \( \cot \theta = \frac{B}{P} \)
    SOH CAH TOA or OSH ACH OTA
  • Trigonometric ratios of standard angles

    	0°	30°	45°	60°	90°
    sin	\( \sqrt{\frac{0}{4}} = 0 \)	\( \sqrt{\frac{1}{4}} = \frac{1}{2} \)	\( \sqrt{\frac{2}{4}} = \frac{1}{\sqrt{2}} \)	\( \sqrt{\frac{3}{4}} = \frac{\sqrt{3}}{2} \)	\( \sqrt{\frac{4}{4}} = 1 \)
    cos	1	\( \frac{\sqrt{3}}{2} \)	\( \frac{1}{\sqrt{2}} \)	\( \frac{1}{2} \)	0
    tan	0	\( \frac{1}{\sqrt{3}} \)	1	\( \sqrt{3} \)	n.d.

  • \( \sin \theta = \frac{1}{\csc \theta} \), \( \csc \theta = \frac{1}{\sin \theta} \)
  • \( \cos \theta = \frac{1}{\sec \theta} \), \( \sec \theta = \frac{1}{\cos \theta} \)
  • \( \tan \theta = \frac{1}{\cot \theta} \), \( \cot \theta = \frac{1}{\tan \theta} \)
  • \( \tan \theta = \frac{\sin \theta}{\cos \theta} \), \( \cot \theta = \frac{\cos \theta}{\sin \theta} \)
  • \( \sin^2 \theta + \cos^2 \theta = 1 \) (mutual understanding)
  • \( \csc^2 \theta - \cot^2 \theta = 1 \) or \( 1 + \cot^2 \theta = \csc^2 \theta \) (csc is big brother)
  • \( \sec^2 \theta - \tan^2 \theta = 1 \) or \( 1 + \tan^2 \theta = \sec^2 \theta \) (sec is big brother)
  • \( \sin(90^\circ - \theta) = \cos \theta \), \( \cos(90^\circ - \theta) = \sin \theta \)
  • \( \csc(90^\circ - \theta) = \sec \theta \), \( \sec(90^\circ - \theta) = \csc \theta \)
  • \( \tan(90^\circ - \theta) = \cot \theta \), \( \cot(90^\circ - \theta) = \tan \theta \)
  • Arithmetic mean on non tabulated data: \( \bar{x} = \frac{\Sigma x}{n} \)
  • Arithmetic mean on tabulated data(Direct Method): \( \bar{x} = \frac{\Sigma fx}{\Sigma f} \) ; \( x \) = mid value (C.I.)
  • Arithmetic mean by Short-cut Method: \( \bar{x} = \frac{\Sigma fd}{\Sigma f} + A \) ; \( A \) = assumed mean, \( d = x - A \)
  • Arithmetic mean by Step-deviation Method: \( \bar{x} = (\frac{\Sigma ft}{\Sigma f}) \times i + A \) ; \( i \) = class width, \( t = \frac{x-A}{i} \)
  • If \( n \) is odd, Median = \( (\frac{n+1}{2})^{\text{th}} \) term
  • For raw data, if \( n \) is even, Median = \( \frac{(\frac{n}{2})^{\text{th}} \text{ term} + (\frac{n}{2}+1)^{\text{th}} \text{ term}}{2} \)
  • For tabulated data, Median = \( L + \frac{\frac{n}{2} - cf}{f} \times h \) term if \( n \) is even and Median = \( L + \frac{\frac{n+1}{2} - cf}{f} \times h \) term if \( n \) is odd.
  • Lower quartile, Q1 = \( (\frac{n+1}{4})^{\text{th}} \) term if \( n \) is odd and \( L + \frac{\frac{n}{4} - cf}{f} \times h \) term if \( n \) is even
  • Upper quartile, Q3 = \( (\frac{3(n+1)}{4})^{\text{th}} \) term if \( n \) is odd and \( L + \frac{\frac{3n}{4} - cf}{f} \times h \) term if \( n \) is even
  • Inter Quartile Range, IQR = Q3 - Q1
  • Semi Inter Quartile Range = \( \frac{Q3 - Q1}{2} \)
  • Mode is the variate which has the maximum frequency.
  • The class with maximum frequency is called the modal class.
  • To estimate mode from histogram: draw two straight lines from the corners of the rectangles on either sides of the highest rectangle to the opposite corners of the highest rectangle. Through the point of intersection of the two straight lines, draw a vertical line to meet the x-axis at the point M (say). The variate at the point M is the required mode.
  • Probability is a measure of uncertainty.
  • An Experiment is an action which results in some (well-defined) outcomes.
  • Sample space is the collection of all possible outcomes of an experiment. n(S)
  • An Event is a subset of the sample space associated with a random experiment. n(E)
  • An Event occurs when the outcome of an experiment satisfies the condition mentioned in the event.
  • The outcomes which ensure the occurrence of an event are called favourable outcomes to that event.
  • The probability of an event E, written as P(E), is defined as \( P(E) = \frac{\text{Number of favourable outcomes}}{\text{Number of possible outcomes}} \)
  • \( P(E) = \frac{n(E)}{n(S)} \)
  • The value of probability is always between 0 and 1.
  • The probability of sure (certain) event is 1.
  • The probability of an impossible event is 0.
  • An elementary event is an event which has one (favourable) outcome from the sample space.
  • A Compound event is an event which has more than one outcome from the sample space.
  • If E is an event, then the event ‘not E' is complementary event of E and denoted by \( \bar{E} \).
  • \( 0 \leq P(E) \leq 1 \)
  • \( P(E) + P(\bar{E}) = 1 \)
  • In a pack (deck) of playing cards, there are 52 cards which are divided into 4 suits of 13 cards each - spades ( \( \spadesuit \) ), hearts ( \( \heartsuit \) ), diamonds ( \( \diamondsuit \) ) and clubs ( \( \clubsuit \) ). Spades and clubs are black in colour, while hearts and diamonds are of red colour. The cards in each suit are ace, king, queen, jack, 10, 9, 8, 7, 6, 5, 4, 3, 2. Kings, queens and jacks are called face (picture/court) cards. The cards bearing number 10, 9, 8, 7, 6, 5, 4, 3, 2 are called numbered cards. Thus a pack of playing cards has 4 aces, 12 face cards and 36 numbered cards. The aces together with face cards (= 16). are called cards of honour.
  • When a coin is tossed, it may show head (H) up or tail (T) up. Thus the outcomes are: {H, T}.
  • When two coins are tossed simultaneously, then the outcomes are: {HH, HT, TH, TT}. [n(S) = \( 2^n \)]
  • When a die is thrown once the outcomes are: {1, 2, 3, 4, 5, 6}. [n(S) = \( 6^n \)]
  • When two dice are thrown simultaneously, then the outcomes are: {(1, 1),(1, 2).......(6, 6)}.