## Algebra and Trigonometry 10th Edition

True. It is because $cos~60°=sin~30°$
$cos~60°-sin~30°=\frac{1}{2}-\frac{1}{2}=0$ Also, remember that $sin(90°-θ)=cos~θ$. So: $sin~30°=sin(90°-60°)=cos~60°$