Attachment 27525

Please need help with this question!

Printable View

- Mar 14th 2013, 01:38 PMcalmo11sin and cosine function
Attachment 27525

Please need help with this question! - Mar 14th 2013, 01:40 PMSironRe: sin and cosine function
Use $\displaystyle (a+b)^2 = a^2+2ab+b^2$.

- Mar 14th 2013, 04:06 PMcalmo11Re: sin and cosine function
I tried doing this and i ended up with 2sin(a)cos(a)=0 where a=alpha, but i am not too sure where to go from there?

- Mar 14th 2013, 11:44 PMMINOANMANRe: sin and cosine function
Calmo

Study trigonometry a little bit. you have to know that 2sinacosa=sin(2a)

therefore you have to solve the equation sin(2a)=0 which is very easy... - Mar 15th 2013, 01:41 AMibduttRe: sin and cosine function
OK

2 sin A cos A = 0 that is when sinA = 0 or cos A = 0

sin A = 0 when A = 0 or pi and cos A = 0 when A = pi/2

I am sure you can finish it now