Question

How do I verify

cos(x+pi/2)=-sinx

its really important please help me!

Answer 1

u know
cos(a + b) = cos(a) cos(b) - sin(a) sin (b)

Answer 2

so cos(x)cos(pi/2)-sin(x)sin(pi/2) ?

Answer 3

yes and evaluate cos(pi/2) and sin (pi/2)

Answer 4

and cos (pi/2) = 0
sin(pi/2) = 1

Answer 5

cos(pi/2) is -0.5 right? and sin(pi/2) is zero

Answer 6

oh

Answer 7

okay so now what

Answer 8

GOT IT thank you !!!!