Evaluate: sin (15600).
Evaluate: cos (–30300).
If sin = 8/17 and cos β = 9/41, find sin (θ + β), cos (θ + β), sin (θ – β) and cos (θ – β), where θ is an obtuse angle and β is an acute angle.
The equation (cos p – 1)x2 + (cos p)x +sin p = 0, where x is a variable, has real roots. Then the interval of p may be any one of the following: