NDA 2016
- Exam
- NDA
- Year
- 2016
- Subject
- Mathematics
- Chapter
- Indefinite Integration
NDA 2016 · Mathematics · Indefinite Integration
What is ∫ e^ x (x ^3 x- x)/( ^2 x) d x equal to?
What is equal to?
Options
- A
- B
- C
- D
Correct answer
B.
Step-by-step solution
Let us differentiate all the options one by one to get the expression in the question whose integral is to be found.
Here is the common term in all the options. So, let us differentiate it first.
Let \begin{aligned}
& =\frac{e^{\sin x}}{\cos ^2 x}\left[x \cos ^3 x+\cos ^2 x+\cos ^2 x+\sin x\right] \\
& =\frac{e^{\sin x}}{\cos ^2 x}\left[x \cos ^3 x+2 \cos ^2 x+\sin x\right]
\end{aligned}\begin{aligned}
& =\frac{e^{\sin x}}{\cos ^2 x}\left[x \cos ^3 x+\cos ^2 x-\cos ^2 x-\sin x\right] \\
& =\frac{e^{\sin x}}{\cos ^2 x}\left[x \cos ^3 x-\sin x\right]
\end{aligned}$ Option (2) is correct.