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

Answer 2

`sin30^o-sin45^ocos45^o\\\\sin30^o=(1)/(2)\\\\sin45^o=cos45^o=(\sqrt2)/(2)\\\\sin30^o-sin45^ocos45^o=(1)/(2)-(\sqrt2)/(2)\cdot(\sqrt2)/(2)=(1)/(2)-(2)/(4)=(1)/(2)-(1)/(2)=0\\\\Answer:a.`