Antiderivatives

Antiderivative of a function is the inverse of the derivative of the function. Antiderivative is also called the Integral of a function. Suppose the derivative of a function d/dx[f(x)] is F(x) + C then the antiderivative of [F(x) + C] dx of the F(x) + C is f(x). This is explained by an example, if d/dx(sin x) is cos x then, the antiderivative of cos x, given as ∫(cos x) dx is sin x.

Antiderivative of any function is used for various purposes, they are used to give the area of the curve, to find the volume of any 3-D curve, and others. In this article, we will learn about, Antiderivatives, Antiderivatives Formulas, Antiderivatives rules, and others in detail.

What are Antiderivatives?

Antiderivative of a function is the reverse operation of the derivative of the function. Mathematically, we also call Antiderivative the Integral of a function.

Suppose, the derivative of the function F(x) is,

F'(x) = f(x)

For all x in the domain of f. If f(x), is the derivative of F(x) then antiderivative or integral of the function f(x) is,

This can be explain by the example lets take a function f(x) = x², on differentiating this function, the output is another function g(x) = 2x.

For, g(x) = 2x the anti-derivative will be, 

f(x) = x²

d/dx[f(x)] = f'(x) = g(x)

g(x) = 2x

Now the antiderivative of 2x is,

= ∫g(x).dx

= ∫(2x).dx

= 2(x²)/2 + C

= x² + C

Here the symbol ∫ denotes the anti-derivative operator, it is called indefinite integrals. Also, C is integration constant, or Antiderivative constant. Antiderivatives are classified into two types,

• Indefinite Antiderivatives
• Definite Antiderivatives

Indefinite Antiderivative

Indefinite antiderative also called the indefinite integral is anti derivative of that function in which the limit of the antiderivative (integration) is not given and the result is accompanied with a constant value (generally C) called the constant of integration. Suppose we have a function F(x) whose derivative is f(x) then,

∫ f(x) dx = F(x) + C

where C is Integration Constant

Definite Antiderivative

Definite Antiderivative or definite integral is the antiderivative of any function inside a closed interval. In this integration the constant of integration is not present and the answer to the integration is some contact value. Suppose we have a function F(x) that is defined on closed interval [a, b] then if its derivative is f(x), its definite antiderative is written as,

∫_a^b f(x) = [F(x)]_a^b = F(b) – F(a)

Rules of Antiderivative

Vrious rules that are used to easily solve problems of Antiderivaties are,

Constant Rule

∫kf(x)dx = k ∫ f(x)dx, here “k” is any constant.

Sum Rule

This rule states that the integral of sum of two functions is equal to sum of integrals of those two functions.

∫(f(x) + g(x))dx = ∫ f(x)dx + ∫g(x)dx

Difference Rule

This rule states that the integral of difference of two functions is equal to difference of integrals of those two functions.

∫(f(x) – g(x))dx = ∫ f(x)dx – ∫g(x)dx

Properties of Antiderivatives

Antiderivative of a function has various properties and the important properties of Antiderivative are,

• ∫-f(x)dx = -∫f(x)dx
• ∫ f(x) dx = ∫g(x) dx if ∫[f(x) – g(x)]dx = 0
• ∫ [k₁f₁(x) + k₂f₂(x) + …+k_nf_n(x)]dx = k₁∫ f₁(x)dx + k₂∫ f₂(x)dx + … + k_n∫ f_n(x)dx

Antiderivatives Formulas

Vrious formula used for finding the antiderivative of the functions are,

• ∫ xⁿ dx = x^{(n + 1)}/(n + 1) + C
• ∫ e^x dx = e^x + C
• ∫ 1/x dx = log |x| + C

Learn More, Integration Formulas

Calculation of Antiderivative of a Function

It is not always possible to just guess the integral of any function by thinking of the reverse differentiation process. A formal approach or a formula is necessary for calculating the Antiderivatives.

To calculate the antiderivative of any function follow the steps added below,

Check the given integral and try to guess the derivative of the function whose antiderivative is to be calculated.

• Use the formulas of integration directly to find the antiderative of any function
• Use substitution method for finding antiderivative of any function.
• Use partial fraction method for finding antiderivative of any function.
• Also use the properties of definite integral for finding antiderivative of definite function.

Example: Find the antiderivative of xⁿ.

Solution:

Antiderivative of xⁿ = ∫ xⁿ dx

Using Integration Formulas

= x⁽ⁿ⁺¹⁾/(n+1) {except when n = -1}

The table below represents some standard functions and their integrals. 

Function	Integral
sin(x)	-cos(x) + C
cos(x)	sin(x) + C
sec2(x)	tan(x) + C
ex	ex + C
1/x	ln(x) + C

Trig Functions Antiderivative

Antiderivative of the trigonometric fuctions is easily found that helps us to solve various problems of integration. Antiderivative of the Trigonometric Functions are,

• ∫ sin x dx = -cos x + C
• ∫ cos x dx = sin x + C
• ∫ tan x dx = -ln |cos x| + C = ln |sec x| + C
• ∫ cot x dx = ln |sin x| + C = -ln |cosec x| + C
• ∫ sec x dx = ln |sec x + tan x| + C
• ∫ cosec x dx = – ln |cosec x + cot x| + C
• ∫ cos (ax + b)x dx = (1/a) sin (ax + b) + C
• ∫ sin (ax + b)x dx = -(1/a) cos (ax + b) + C

There are some functions whose antiderivative gives Inverse Trigonometric Functions that are,

• ∫ 1/√(1 – x²).dx = sin^-1x + C
• ∫ 1/(1 – x²).dx = -cos^-1x + C
• ∫ 1/(1 + x²).dx = tan^-1x + C
• ∫ 1/(1 + x²).dx = -cot^-1x + C
• ∫ 1/x√(x² – 1).dx = sec^-1x + C
• ∫ 1/x√(x² – 1).dx = -cosec^-1x + C

Read More,

• Differentiation and Integration Formulas
• Area Under Curve
• Area Between Curve

Examples on Antiderivatives

Example 1: Find the integral for the given function, 

f(x) = 2x + 3

Solution: 

Using Integral Formula,

Given,

f(x) = 2x + 3

Splitting the function

⇒

⇒

⇒

⇒ x² + 3x + C

Example 2: Find the integral for the given function, 

f(x) = x² – 3x

Solution:

Using Integral Formula,

Given,

f(x) = x² – 3x

Splitting the function

⇒

⇒

Example 3: Find the integral for the given function, 

f(x) = x³ + 5x² + 6x + 1

Solution: 

Using Integral Formula,

Given,

f(x) = x³ + 5x² + 6x + 1

Splitting the function

⇒

⇒

Example 4: Find the integral for the given function, 

f(x) = sin(x) – cos(x)

Solution: 

Using Integral Formula,

Given,

f(x) = sin(x) – cos(x)

Splitting the function

⇒

⇒

Example 5: Find the integral for the given function, 

f(x) = 2sin(x) + sec²(x) + 7e^x

Solution: 

Given,

f(x) = 2sin(x) + sec²(x) + 7e^x

Splitting the function

⇒

⇒

⇒

Example 6: Find the integral for the given function, 

f(x) = 

Solution: 

Using Integral Formula,

Given,

f(x) = 

Splitting the function

⇒

⇒ x – 3ln(x) + C

Example 7: Find the integral for the given function, 

f(x) = x² – 4x + 4

Solution: 

Using Integral Formula,

Given,

f(x) = x² – 4x + 4

Splitting the function

⇒

Practice Questions on Antiderivatives

Q1: ∫1/√x dx

Q2: ∫a^2log_a^x dx

Q3: ∫2/(1 + cos 2x)dx

Q4: ∫3^x+3dx

Q5: ∫1/2tan x dx

FAQs on Antiderivatives

1. What is Antiderivative?

Andtiderivative as the name suggest is the inverse operation of derivative of any function. Antiderivative is also called Integration. Suppose the derivative of any function f(x) is F(x) then the anti derivative of F(x) is f(x) + C where, C is integration constant.

2. Are Antiderivatives Same as Integrals?

Yes, antiderivative are similar to integral. They are equivalent in mathematics and can be used alternatively.

3. What is the Power Rule for Antiderivatives?

Power rule in antiderivative states that antiderivative of a function xⁿ (where the value of one is never equal to -1) is given using the formula,

∫ xⁿ dx = x^{(n + 1)}/(n + 1) + C

4. What is the Antiderivative of 1 / x?

Antiderivative of 1 / x is given by the formula,

∫1/x.dx = ln|x| + C

5. What is Antiderivative of Sin x?

Antiderivative of Sin x is,

∫sin x.dx = -cos x + C

6. What is Antiderivative of Cos x?

Antiderivative of Cos x is,

∫cos x.dx = sin x + C

7. What is Antiderivative of Tan x?

Antiderivative of Tan x is,

∫tan x.dx = ln |sec x| + C