Question

4cos^3 15°-3 cos15°=​

Answer 1

Step-by-step explanation:

$4 { \cos(15) }^{3} - 3 \cos(15) = \cos(3 \times 15) \\ \\ = \cos(45) \\ \\ = \frac{1}{ \sqrt{2} } .$

Answer 2

4cos(15)

3

−3cos(15)=cos(3×15)

=cos(45)

=

1/√2