### Home > CCA2 > Chapter 12 > Lesson 12.2.3 > Problem12-131

12-131.

Write each angle as the sum or difference of two special angles and then find the exact sine or cosine. Homework Help ✎

1. sin$\frac { 7 \pi } { 12 }$

Refer to problem 12-130. Find a way to add or subtract two familiar angles from the unit circle to get the desired angle. Then use the appropriate identity from the Math Notes in Lesson 12.2.3.

$\sin\left(\frac{\pi}{3}+\frac{\pi}{4}\right)\ =\ \frac{\sqrt{6}+\sqrt{2}}{4}$

1. cos$\frac { 11 \pi } { 12 }$

Use the same method as part (a).