$\int \frac{dx}{(\sin x)(\cos x)}$ is equal to

$\int {\frac{{a{x^3} + b{x^2} + c}}{{{x^4}}}\,dx} $ equals to

$\int \frac{1}{x^2}(2 x+1)^3 d x$ is equal to

$\int {\frac{{{x^2}dx}}{{{{(a + bx)}^2}}}} = $

Consider the following statements $(A)$ and $(B)$:
$(A) \int_a^b \frac{d}{d x}(f(x)) d x = \frac{d}{d x} \int_a^b f(x) d x$
$(B) \frac{d}{d x} \left( \int f(x) d x \right) = f(x) + C$
Which one of the following is true?

$\int {\frac{{1 + {{\tan }^2}x}}{{1 - {{\tan }^2}x}}\,dx} $ is equal to