sin(3pi/12)cos(pi/12)+cos(3pi/4)sin(pi/12)

I tried it like this sqrt2/2 (sqrt2/4+sqrt6/4)+(-sqrt2/2+?

I'm not sure if how to approach it (Worried)

Printable View

- June 21st 2011, 11:30 AMLAPOSH42Exact Value of the expression without a calculator
sin(3pi/12)cos(pi/12)+cos(3pi/4)sin(pi/12)

I tried it like this sqrt2/2 (sqrt2/4+sqrt6/4)+(-sqrt2/2+?

I'm not sure if how to approach it (Worried) - June 21st 2011, 12:00 PMPlatoRe: Exact Value of the expression without a calculator
- June 22nd 2011, 01:59 AMwaqarhaiderRe: Exact Value of the expression without a calculator
sin(3pi/12) = sin(pi/4) and cos(3pi/4) = -cos(pi/4) so your expression becomes

sin(pi/4)cos(pi/12) - cos(pi/4)sin(pi/12) = sin[(pi/4) - (pi/12)] => sin(pi/6)