化简 :sin(a+b)cos(r-b)-cos(b+a)sin(b-r) sin(a-b)sin(b-r)-cos(a
sin(a-b)sin(b-r)-cos(a-b)cos(r-b)
cos(a+b)+cos(a-b)/sin(a+b)+sin(a-b)化简
sin(a+B)cos(y-B)-cos(B+a)sin(B-y) 化简
cos(a+b)=cos(a)*cos(b)-sin(a)*sin(b) 用三角形证明
由cos(a+b)=cos a cos b-sin a sin b cos(a-b)=cos a cos b+sin a
化简 sin^4a-cos^4b
cos(a-b)cos(b-c)+sin(a-b)sin(b-c)=
sin^2 (A)+sin^2(B)-sin^2(A)sin^2(B)+cos^2(A)cos^2(B)
sin平方a*cos平方b-cos平方a*sin平方b为什么等于sin平方a-sin平方b?
貌似不难,sin(a+b)cos(c-b)-cos(b+a)sin(b-c)sin(a-b)sin(b-c)-cos(a
化简[sin(2A+B)]/sinA-2cos(A+B)
化简:cos(A-B)cosB-sin(A-B)sinB