1+sin2B/cos^2B-sin^2B=-3
1+sin2B/cos^2B-sin^2B=-3
为什么1/2(sin2A+sin2B)=sin(A+B)cos(A-B)
已知A,B,C是三角形ABC的三个内角,若1+sin2B/(cos^2B-sin^2B) =2+根号3,求角B
证明2sin(a+b)cos(a-b)=sin2a+sin2b
求证:tan(a+b)-tana\1+tanatan(a+b)=sin2b\2cos^2b
tan(a+b)=3tana 证明2sin2b-sin2a=sin(2a+2b)
已知3Sin2b=sin(2a+b)证明:tan(a+b)=2tana
已知a,b均为锐角,且3sin^2a+2sin^2b=1,3sin2a-2sin2b=0,求a+2b?
已知a b为锐角,且3sin^2a=2sin^b=1,3sin2a-2sin2b=0,
已知a+b,a-b均为锐角,且sin(a+b)=2根5/5,cos(a-b)=3根10/10,求sin2b的值
已知sin2A-sin2B=0,问为什么cos(A+B)sin(A-B)=0
已知sin^4b+cos^4b=5/9,求sin2b的值.