Which function is equivalent to y= -cot(x)? a. y= -tan(x) b. y= -tan (x+ pi/2) c. y= tan(x) d. y= tan (x+pi/2)

We know that
tan (A+B)=sin (A+B)/cos (A+B)
sin (A+B)=sin A*cos B+sin B*cos A
cos (A+B)=cos A*cos B-sin A*sin B
so
for (x+pi/2)
A=x
B=pi/2
sin A=sin x
sin B=1
cos A=cos x
cos B=0
sin (A+B)=sin x*0+1*cos x> cos x
cos (A+B)=cos x*0-sin x*1> -sin x
tan (x+pi/2)=cos x/(-sin x)> -cot x

the answer is the option
D. y= tan (x+pi/2)

The answer would be b