Part4: (Surn and difference identities) Show all your work. a) Fadel calculated sin(135) as shown below: V2 V2+2 sin(135) = sin(90 + 45)° = sin 90° + sin 45º = 1 + 2 Is Fadel correct in his calculation, if NOT, Correct the calculation to get the correct answer.(3marks) DA b) Use the formula sin(A + B) = sin A cos B + cos A sin B to show sin 2x = 2 sin x cos x (Hint: Take A=B=x) (2marks) c) Use the formula cos(A + B) = cos A cos B-sin A sin B to show cos 2x = 1 - 2 sin²x. (5marks) d) Use the formula sin(A + B) = sin A cos B + cos A sin B AND the answers of parts b and c to show that sin 3x = 3 sin x-4 sin³ x
