化简[(cos^2a-sin^2B)/(sin^2a*cos^2B)]-cot^2a*cot^2B

化简cos(a+b)cos(a-b)+sin^2b 化简sin^2a+sin^2b-sin^2a*sin^2b+cos^2a*cos^2b sin^2a+sin^2b-sin^2a * sin^2b+cos^2a * cos^2b 化简 化简（sin(a-b)-2sin a cos b）/2sin a sin b +coa(a+b) 化简sin^2acos^b-cos^2asin^2b+cos^a-cos^2b 化简[sin(2A+B)]/sinA-2cos(A+B) 化简[(cos^2a-sin^2B)/(sin^2a*cos^2B)]-cot^2a*cot^2B 化简cos（a+b）cos（a-b）+sin^2b sin^2 (A)+sin^2(B)-sin^2(A)sin^2(B)+cos^2(A)cos^2(B) 证明 sin^2A+sin^2B-sin^2A*sin^2B+cos^2A*cos^2证明 sin^2A+sin^2B-sin^2A*sin^2B+cos^2A*cos^2B=1 cos^2a-cos^2b=m,那么sin(a+b)sin(a-b)=? 证明sin(A+B)sin(A-B)=cos^2B-cos^2A 化简：sin^2a+sin^2b+2sina*sinb*cos(a+b) sin∧2a+sin∧2b+2sina*sinb*cos(a+b).化简, 求证cos(a+b)cos(a－b)=cos^2b－sin^2a 求证cos(a+b)cos(a-b)=cos^2a-sin^2b 化简sin^2(a)*sin^2(b)+cos^2(a)*cos^2(b)-1/2cos2a*cos2b sin(a-b)*cos a-cos(a-b)*sin a=1/5,则cos 2b的值是