Introduction (Integration)
Integration is the reverse process of differentiation. It is also called anti-differentiation.
Integral calculus has its own application in economics, Engineering, Physics, Chemistry, business, commerce, etc.
The integral of a function is denoted by the sign
Let the function is y = f(x),
Its derivative is-
Then
Where c is the arbitrary constant.
For example,
A function,
Then, its derivative-
Or
Then-
Here c is an arbitrary constant.
Some fundamental integrals
Methods of integration
Simple integration-
1. When the function is an algebraic function-
Some standard results-
- If dy = f’(x) dx, then
- If dy = a [f’(x) dx] where a is constant, then-
The integration of x^n will be as follows-
Example: Find the integral of-
Sol:
We know that-
hence,
Example: Find the integral
Sol.
We know that-
then
Integration by substitution
Example: Evaluate the following integral-
Sol:
Let us suppose,
or
therefore, Substituting –
Logarithmic function
Example: Evaluate the following integral-
Sol:
Let us suppose-
Integration of exponential function
Example: Evaluate-
Sol:
Let
Now substituting-
Method for product of two functions
Suppose we have two function say- f(x) and g(x), then
The integral of product of these two functions is-
Note-
We chose the first function as method of ILATE-
Which is-
I – Inverse trigonometric function
L – Log function
A – Algebraic function
T- Trigonometric function
E- Exponential function
Example: Evaluate-
Sol:
Here according to ILATE,
First function = log x
Second function =x^n
We know that-
Then-
On solving, we get-
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