Question

find the value of 3 sin alpha - 4cos cube alpha if sin alpha=1/2​

Answer 1

Answer:-

$\frac{3}{2} (1 - \sqrt{3} )$

Solution:-

sin alpha =1/2

=sin alpha =sin π/6

=cut sin both side

=alpha =π/6

putting the value of alpha in equation

$3 \times \frac{1}{2} - 4 \times \cos( \frac{\pi}{6} ) {}^{3}$

=3/2-4×(√3/2)^3

=3/2-4×3√3/8

=3/2-3√3/2

=common 3/2

=3/2(1-√3)