Question

if 3sinB +5cosB=5,then 3cosB -5sinB is equal to?​

Answer 1

Answer:

sinB=1/2

sin30°=1/2

So, B=30°

=3cosB-4cos³B

=3cos30°-4(cos30°)³

[Using cos30°=√3/2]

=3×(√3/2)-4×(√3/2)³

=(3√3/2)-4×(3√3/8)

=(3√3/2)-(3√3/2)

=0

Answer 2

Answer:

i think 63/65 is the suitable answer.