2.
2008/November/Qn. 6
Express 5 sin x + 12 cos x in the form R sin(x + a), where R > 0 and 0° < a < 90°,
giving the value of a correct to 2 decimal places.
Hence solve the equation 5 sin20 + 12 cos 20= 11, giving all solutions in the interval
0° <0 < 180°.