trigonometry

Hi eveybody,

I have a TI-89.I would like to solve this trigonometric equation: sin((pi/4)-2x)-sin(x)=0.

I would like to know the EXACT results but the TI-89 will give me the approximate results only.Can anyone tell me why?

Can't I optain the exact solutions for this equation.

I have also found that the TI-89 is not very strong in trigo functions.For example you cannot optain a trigo expression

with tan,sin,cos or what you want.

Thank you a lot for help.

Carl ANTAKI.