Question

How do you solve `Sin(x + pi/4) + Sin(x - pi/4) = -1`?

Answer 1

Solutions in [0, 2`pi`] are 5`pi`/4 and 7`pi`/4.

Explanation:

Use sin (A+B) + sin(A`-`B) = 2 sin 2A sin 2B.
The equation reduces to sin x = `-`1/`sqrt`2.