Question

13. Find the exact value of sin 30 ° - sin 45 ° cos 45 ° . a. 0 b. 1/2 c. 1 d. 2

Answer 1

$sin30^o-sin45^ocos45^o\\\\sin30^o=\frac{1}{2}\\\\sin45^o=cos45^o=\frac{\sqrt2}{2}\\\\sin30^o-sin45^ocos45^o=\frac{1}{2}-\frac{\sqrt2}{2}\cdot\frac{\sqrt2}{2}=\frac{1}{2}-\frac{2}{4}=\frac{1}{2}-\frac{1}{2}=0\\\\Answer:a.$

Answer 2

Sin30  1/2
sin45*cos45=1/2
=>  1/2  -  1/2 = 0