Question

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)

Answer 1

D. y = tan(x + pi/2)

Explanation:

this is the correct answer on ed-genuity, hope this helps! :)

Answer 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)