SOLUTION: cos(x+pi/2)=-sin x

Question 861329: cos(x+pi/2)=-sin x

Answer by math-vortex(648) (Show Source): You can put this solution on YOUR website!

Hi there,

PROBLEM:
Prove that the identity is true.
cos(x+pi/2)=-sin (x)

Solution:
Transform the left side of the identity until is is the same as the right side.
cos(x + pi/2) = -sin (x)
cos(pi/2 - (-x)) = -sin (x)

Apply the co-function property: [cos(pi/2 + x) = sin (x)]
sin (-x) = -sin (x)

Apply the even/odd formula: [sin (-x) = - sin (x)]
-sin (x) = - sin (x)

That's it.

Mrs. Figgy
math.in.the.vortex@gmail.com

RELATED QUESTIONS
cos(x+pi/2) =... (answered by MathLover1)

prove... (answered by lwsshak3)

(sin(x+pi))/(cos(x-pi)) (answered by stanbon)

verify the identity cos (x + pi/2) = -sin... (answered by tommyt3rd)

verify the identity. cos (x + pi/2) = - sin... (answered by Theo,MathLover1)

Verify the identity. cos( x (pi/2)) = -sin x (answered by Alan3354)

limit... (answered by Fombitz)

Solve 2 sin^2 x + cos x -2=0 on the interval -pi< x <... (answered by lwsshak3)

sin(pi/2)-x (answered by stanbon)