5 5.2 5.1.1 cos 2A 5.1.2 sin (A + B) Simplify, without the use of a calculator: sin 20° cos 320° + cos (-20°) sin (400°) 5.3 Prove the identity: cos² (90° + 0) -e) cos (-) + sin (90° - 0) cos 0 1 cos 0 5.4 It is given that p = cos a + sin a q = cos a - sin a deduce the following trigonometric ratios in terms of par 5.4.1 cos 2a 5.4.2 1 + sin 2a cos 2a Determine the general solution of 6 cos² x + sin x-5=​