Question:

Integrate the function: \(\frac{x^3 \sin(\tan^{-1}x^4)}{1+x^8}\)

Updated On: Oct 19, 2023
Hide Solution
collegedunia
Verified By Collegedunia

Solution and Explanation

Let x4 = t

∴ 4x3 dx = dt

\(\Rightarrow \int\frac{x^3 \sin(\tan^{-1}x^4)}{1+x^8}dx=\frac{1}{4}\int\frac{\sin (\tan^{-1})}{1+t^2}dt\)

Let \(\tan^{-1}t=u\)

∴ \(\frac{1}{1+t^2}dt = du\)

From (1), we obtain

\(\int\frac{ x^3\sin(tan^{-1}x^4)dx}{1+x^8}=\frac{1}{4}\int\sin u \; du\)

\(\frac{1}{4}(- \cos u)+C\)

=\(\frac{-1}{4}\cos(\tan^{-1}t)+C\)

=\(\frac{-1}{4}\cos (\tan^{-1}x^4)+C\)

Was this answer helpful?
0
0

Concepts Used:

Methods of Integration

Given below is the list of the different methods of integration that are useful in simplifying integration problems:

Integration by Parts:

 If f(x) and g(x) are two functions and their product is to be integrated, then the formula to integrate f(x).g(x) using by parts method is:

∫f(x).g(x) dx = f(x) ∫g(x) dx − ∫(f′(x) [ ∫g(x) dx)]dx + C

Here f(x) is the first function and g(x) is the second function.

Method of Integration Using Partial Fractions:

The formula to integrate rational functions of the form f(x)/g(x) is:

∫[f(x)/g(x)]dx = ∫[p(x)/q(x)]dx + ∫[r(x)/s(x)]dx

where

f(x)/g(x) = p(x)/q(x) + r(x)/s(x) and

g(x) = q(x).s(x)

Integration by Substitution Method

Hence the formula for integration using the substitution method becomes:

∫g(f(x)) dx = ∫g(u)/h(u) du

Integration by Decomposition

Reverse Chain Rule

This method of integration is used when the integration is of the form ∫g'(f(x)) f'(x) dx. In this case, the integral is given by,

∫g'(f(x)) f'(x) dx = g(f(x)) + C

Integration Using Trigonometric Identities