Exercise
$-\cos\left(x-\frac{\pi}{2}\right)=-\sin\left(x\right)$
Step-by-step Solution
Learn how to solve proving trigonometric identities problems step by step online. Prove the trigonometric identity -cos(x-pi/2)=-sin(x). Starting from the left-hand side (LHS) of the identity. Using the cosine of a sum formula: \cos(\alpha\pm\beta)=\cos(\alpha)\cos(\beta)\mp\sin(\alpha)\sin(\beta), where angle \alpha equals x, and angle \beta equals -\frac{\pi }{2}. The sine of -\frac{\pi }{2} equals -1. Multiply -1 times -1.
Prove the trigonometric identity -cos(x-pi/2)=-sin(x)
Final answer to the exercise
true