Find the derivative of the following functions

Let $f(x)=\frac{a+b \sin x}{c+d \cos x}$

By quotient rule,

$f^{\prime}(x)=\frac{(c+d \cos x) \frac{d}{d x}(a+b \sin x)-(a+b \sin x) \frac{d}{d x}(c+d \cos x)}{(c+d \cos x)^{2}}$

$=\frac{(c+d \cos x)(b \cos x)-(a+b \sin x)(-d \sin x)}{(c+d \cos x)^{2}}$

$=\frac{c b \cos x+b d \cos ^{2} x+a d \sin x+b d \sin ^{2} x}{(c+d \cos x)^{2}}$

$=\frac{b c \cos x+a d \sin x+b d\left(\cos ^{2} x+\sin ^{2} x\right)}{(c+d \cos x)^{2}}$

$=\frac{b c \cos x+a d \sin x+b d}{(c+d \cos x)^{2}}$