Question

$(3x^{2} + 5) = t$

• A. $\int_{}^{}{\frac{\sec^{2}x}{(1 + \tan x)(2 + \tan x)}\mspace{6mu} dx}$
• B. $1 + \tan x = t$
• C. $2 + \tan x = t$
• D. $\tan x = t$

Answer 1

Answer: (D)

$\tan x = t$

Answer 2

$\log\left( \frac{1}{x - 2\log x} \right) + c$

$\int_{}^{}{x\sqrt{1 + x^{2}}}\mspace{6mu} dx =$.