Help me find the last pet

Score: 0.67 of 1 pt 1.3.57 Apply the law of cosines to the triangle in the accompanying figure to derive the y + formula for cos (A - B) X Q Find the length of x. To do so, first determine the coordinates of points P and Q. Point P is ( cos A, sin A) . (Type an ordered pair.) Point Q is ( cos B, sin B) . (Type an ordered pair.) Now use the distance formula to find the length of x. x = 1( cos B - cos A) + ( sin A - sin B)2 Next substitute the expression for x into the equation found using the law of cosines and simplify. x2 = 12 + 12 - 2(1)(1) cos (A - B) - 2 cos (A) cos (B) + 2 -2 sin (A) sin (B) =2-2 cos (A - B) (Simplify your answer.) Finally, solve for cos (A - B). COS (A - B) =|