Find the exact value of sin²75°, given that sin15° = (√3 -1)/2√2.
Could someone please explain to me the relevance of sin15° in finding sin²75°?
Thanx
Sorry, whats confusing you? often you are expected to memorize the sin and cosine of some comon angles, such as $\displaystyle 30^{\circ},45^{\circ},60^{\circ}, $etc.
The fomula is for the sine of the sum of two angles. Have you seen this yet? I just realised you don't have the cosines of the angles anyway, so probably you have to draw a diagram, label the sides of the triangles, and remember $\displaystyle cos(\theta)=\frac{adjacent}{hypotenuse}$