Explain how to use half-angle identities to find the exact value of sin 7.5⁰. To find the exact value of sin 7.5°, use two half-angle identities in succession. Using the first identity allows sin 7.5° to be rewritten as Rewrite the trigonometric expression within the radical using a second identity. Complete the rewrite below. Substitute the rewritten expression from the previous step into the radical expression from the first step. The result simplifies to sin 7.5° =