求证 cos(A)+ 根号3sin(A)=2sin(π/6+A)
求证 cos(A)+ 根号3sin(A)=2sin(π/6+A)
已知tan a=3,求下列各式的值;(1)根号3 cos a-sin a/根号3 cos a+sin a (2)2sin
求证:tan(2π-a)sin(-2π-a)cos(6π-a)/cos(a-π)sin(5π-a)=-tana
求证:sin a (1+cos2a)=sin a cos a
求证:tan a/2=(1-cos)/sin a=sin a/(cos a+1)
求证sin(90+a)=cos a
求证 2(1-sin a)(1+cos a)=(1-sin a + cos a)^2
求证tan(2π-a)cos(3π/2 -a)cos(6π -a) / sin(a+3π/2)cos(a+3π/2) =
(1)已知cos[(π/3)-a]=根号3/3,求sin[5π/6)-a]+sin^2[(2π/3)+a]的值
求证:【tan(2π-a)sin(-2aπ-a)cos(6π-a)】/【sin(a+3π/2)cos(a+3π/2)】=
求证:tan(2π-a) sin(-2π-a) cos(6π-a) / cos(a-π) sin(5π-a)=-tana
已知a属于(0,π/2),且2sin^2 a-sin a cos a-3cos^2 a=0,求SIN(a+兀/4)/SI