Now let us investigate whether the identity of cos(a−b)=cos(a)cos(b)+sin(a)sin(b), is true for all values of a and b. Let P(cos(a),sin(a)) and Q(cos(b),sin(b)) be any two points on the circle O with radius 1. If P′=(a) and Q′=(b) then POQ=a−b. True/False?
a) True
b) False