$\int e^{x}\left(\tan^{-1}x+\dfrac{1}{1+x^2}\right)dx$ equals
A$e^{x}\tan^{-1}x+C$
B$e^{x}\left(\tan^{-1}x-\dfrac{1}{1+x^2}\right)+C$
C$\tan^{-1}x+C$
D$\dfrac{e^{x}}{1+x^2}+C$
Answer & Solution
Correct answer: A. $e^{x}\tan^{-1}x+C$
1. Let $f(x)=\tan^{-1}x$, then $f'(x)=\dfrac{1}{1+x^2}$.
2. The integrand is $e^{x}[f(x)+f'(x)]$.
3. Using $\int e^{x}[f(x)+f'(x)]\,dx=e^{x}f(x)+C$.
4. Result: $e^{x}\tan^{-1}x+C$.
_Source: NCERT Class 12 Mathematics Ch 7 "Integrals", p.328_
Related questions
When variables and numbers appear on both sides, you must simplify:Equations needing more than one operation are described as taking more:Once a solution is found, it should be checked by substituting it back to get a statement The product of any number and its reciprocal equals:A fraction multiplying the variable is best removed by multiplying by its:Solving x divided by 4 equals 3 gives x equal to:Solving 4x equals 20 gives x equal to:Solving x minus 8 equals 5 gives x equal to: