Question

Bol') ( cos ^{2}(A-B)+cos ^{2} B-2 cos A cos B cos )
( =(cos A cos B+sin A sin B)^{2}+cos ^{2} B-frac{2 cos A cos B}{cos (A-B)} )
( =cos ^{2} A cos ^{2} B+frac{sin ^{2} sin ^{2} B+2 sin A sin B cos A cos B}{+cos ^{2} B-2 cos A cos B} )
( (cos A cos B+sin A sin B) )
( cos ^{2} A cos ^{2} B+sin ^{2} A sin ^{2} B+2 sin A sin ^{2} )
( cos A cos B+cos ^{4} )
( -2 cos ^{2} A cos ^{2} B-2 cos A cos B sin A )
( cos ^{2} A cos ^{2} B+sin ^{2} A sin ^{2} B+cos ^{2} B-2 cos ^{2} A cos ^{2} B )
( -cos ^{2} A cos ^{2} B+sin ^{2} A sin ^{2} B+cos ^{2} B )
( =0.008^{2} Bleft(1-cos ^{2} Aright)+sin ^{2} A sin ^{2} B )
( =sin ^{2} B sin ^{2} A+sin ^{2} A sin ^{2} B )
( =2(sin A sin B)^{2} )

# COS? (A-B) tcOS?B - 2 COSA COSB COS(AB,

Solution