# Integration Formula

## Basic Integration

 Power Rule (i) ∫ 1 dx = x + C ∫ xn dx = x^{n+1}\over n+1 + C Exponential Function (ii) ∫ex dx = ex + C ∫emx dx = 1\over memx + C (iii) ∫ax dx = ax ln a + C ∫amx dx = 1\over mamx ln a + C (iv) ∫1\over x dx = ln |x| + C ∫1\over mx dx = ln |x| + C Trigonometric Functions (iii) ∫sin(x) dx = -cos(x) + C ∫sin(mx) dx = – 1\over mcos(mx) + C (iv) ∫cos(x) dx = sin(x) + C ∫cos(mx) dx = 1\over m sin(mx) + C (v) ∫sec(x)tan(x) dx = sec(x) + C ∫sec(mx)tan(mx) dx = 1\over msec(mx) + C (vi) ∫sec2(x) dx = tan(x) + C ∫sec2(mx) dx = 1\over mtan(mx) + C (vii) ∫cosec2(x) dx = -cot(x) + C ∫cosec2(mx) dx = –1\over mcot(mx) + C (viii) ∫cosec(x)cot(x) dx = -cosec(x) + C ∫cosec(mx)cot(mx) dx = –1\over mcosec(mx) + C (ix) ∫tan(x) dx = -ln|cos x| + C (x) ∫cot(x) dx = ln|sin x| + C (xi) ∫cot(x) dx = ln|sin x| + C (xii) ∫sec(x) dx = ln|sec x + tan x| + C (xiii) ∫cosec(x) dx = ln|cosec x – cot x| + C

 (i) ∫1\over \sqrt{a^2-x^2} dx = sin-1 x\over a + C (ii) ∫{1\over {a^2 +x^2} } dx = 1\over a tan-1 x\over a + C (iii) ∫1\over x \sqrt{x^2-a^2} dx = 1\over a sec-1 x\over a + C (iv) ∫1\over \sqrt{x^2+a^2} dx = ln |x + \sqrt{x^2+a^2}| (v) ∫1\over \sqrt{x^2-a^2} dx = ln |x + \sqrt{x^2-a^2}| (vi) ∫\sqrt{a^2-x^2} dx = x\sqrt{a^2-x^2}\over 2 + a^2\over 2sin-1x\over a + C (vii) ∫\sqrt{a^2+x^2} dx = x\sqrt{a^2+x^2}\over 2 + a^2\over 2ln |x + \sqrt{a^2+x^2}| (viii) ∫\sqrt{x^2-a^2} dx = x\sqrt{x^2-a^2}\over 2 + a^2\over 2ln |x + \sqrt{x^2-a^2}| (ix) ∫1\over x^2-a^2 dx = {1\over 2a} ln |{x-a\over x+a}| (x) ∫1\over a^2-x^2 dx = {1\over 2a} ln |{a+x\over a-x}|

## Integration by part

∫uv dx = u∫vdx – ∫[du/dx∫vdx]dx

U and V is selected on the basis of ILATE

Where

• I → Inverse trigonometry
• L → Logarithmic function
• A → Algebraic function
• T → Trigonometric function
• E → Exponential

## Some Special Integration

1. ∫ {f ‘(x)/f (x) } dx = ln f(x) + C
2. ∫ex [f(x) + f ‘(x)] dx = ex f(x) + C

## Definite Integrals

\int_a^b f(x) dx = [F(x)]_a^b = F(b) – F(a)

## Summation of Series by Definite Integral

Let f(x) be a continuous function in [a, b] and h be the length of n equal subintervals, then

\int_{a}^{b} \ f(x) \, dx = \lim_{n \to \infty } h \sum_{r=0}^{n}{f(a+rh)}

where, nh = b – a

Now, put a = 0, b = 1

∴ nh = 1 – 0 = 1 or h = 1/n

\int_{0}^{1} \ f(x) \, dx = \lim_{n \to \infty } {1\over n} \sum_{r=0}^{n-1}{f(r/n)}

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