Question

Can anyone please help : show that cos^{2} (θ)= 1 + cos(2θ) / 2 , using the compound angle formula

Answer 1

Below

Explanation:

Let's prove that cos^2(O) = 1+ cos(2O)/2

We khow that cos(2O) = 2 cos^2-1

● cos(2O) = 2 cos^2-1

Add one to both sides:

● cos(2O) +1 = 2 cos^2-1+1

● cos(2O) +1 = 2 cos ^2

Divide both sides by 2

● [cos(2O)+1]/2 = cos^2