Question

How do you use product to sum formulas to write the product `6sin15^circsin45^circ` as a sum or difference?

Answer 1

`6sin15^@sin45^@=3sqrt3-3`

Explanation:

As `cos(A-B)-cos(A+B)=2sinAsinB`

`6sin15^@sin45^@=6sin45^@sin15^@`

= `6cos(45^@-15^@)-6cos(45^@+15^@)`

= `6cos30^@-6cos60^@`

= `6xxsqrt3/2-6xx1/2`

= `3sqrt3-3`