Question

Evaluate sin2 (pi/4) + cos2 (pi/4).

Answer 1

`sin^2(\pi/4)+cos^2(\pi/4)=1`

Explanation:

Notice that you don't need to evaluate the actual sin and cos functions, since you are in the presence of a well known Pythagorean identity that states that this type of addition of squares for the same angle should equal 1:

`sin^2(x)+cos^2(x)=1`

So, as long as the angle "x" is the same in both trig functions, this addition should render "1" (one).

Because in this case the angle involved is the same (in both cases pi/4), the identity is valid.