Trigonometric Questions....?

Question

sin(-11pie/6)=

a)-sin pie/5 b)-sin pie/4 c)-sin pie/3 d)-sin pie/6 e)not givn


cos(-2448degrees)=

a)cos58deg b) -cos58deg c) -cos72deg d)cos72deg e)not given


PLease Show Your work....or write you reasoning

Thank You for your help! As for Smartprimate, I appreciate your concern but I understand it perfectly =)

Answer 1

I´llshow you some work
sin(-11pi/6) = -sin(11pi/6) sin is an odd function = -sin(-pi/6)
I rested 2pi = sin(pi/6)=1/2

-sin(pi/4) = -sqrt2 / 2 -sinpi/3 = sqrt3 /2 -sin pi/5=-0.5878

cos(-2448degrees) = cos ( 2448 degrees) cos is an even function

Divide 2448 into 360 and take the whole part off.It is 6
Substract 6*360 from your angle.You´ll get an angle with the same trigonometrics lines =288 degrees which is between 0 and 360 and has the same cos as72 degrees = 0.3090

Answer 2

Stop asking specific questions that don't ask for help in understanding. Doing these problems for you will not help.

Answer 3

sin (-11π/6) = sin (-11π/6 + 2π)
= sin (-11π/6 + 12π/6)
= sin (π/6).

cos (-2448°) = cos (-2448° + 7*360°)
= cos (-2448° + 2520°)
= cos (72°).