sinA+2根号3cos^2 A/2=2根号3 求A
sina+cosa=-3/根号5,且|Sina|>|cos a|,求tan(a/2)
已知sinA+sinA=根号2/3(A在90度到180度之间),求(1)sinA-cosA.(2)sinA的三次-cos
sin(a+π/3)+sina= - 4根号3/5,则cos(a+2π/3)
已知sina-cosa=-根号3/2,则sin a*cos a=
sina=3/5,a∈(0,π/2),求tan2a+根号2cos(a-π/4)
已知sina+sinb=根号2 cosa+cosb=2根号3/3。 求cos(a-b),tan(a+b)/2,sin(a
sina-cosa=(根号2)/5,求sin(π+a)+cos(π-a)=?
已知sina+cosa=根号2,求sinacosa,tana,sin^4a+cos^4a
急解!已知sina+sinb=根号2 cosa+cosb=2根号3/3. 求cos(a-b),tan(a+b)/2,si
设tan2a=-2根号2,求cos^a/根号2-sina-1/2sin(a+/pai4)
已知角a终边上一点p (-根号3 ,y) 且sina=( 根号2 /4 )*y,求cos a 会的帮下忙,
设tan2a=2根号2,a属于(π/2,π),求(2cos^a/2-sina-1)/(sina+cosa)