<aside> 💡 Just like exponential and logarithmic function—or like the arc-trig and trig—We are finding the input before the derivation.
</aside>
Remember that $\ln a$ is constant. Never try to cancel a variable term….
$\int \cos x dx=\sin x+C$
$\int \sec ^2x dx=\tan x+ C$
$\int \sec x \tan x dx=\sec x+C$
$\int \sin x dx=-\cos x+C$
$\int \csc^2x dx=-\cot x+C$
$\int \csc x \cot x dx= -\csc x +C$
$\int \tan x = -\ln (\cos x)+C$. no
$\int \cot xdx = \ln (\sin x)+C$
$\int \sec x dx=\ln |\sec x+\tan x|+C$