已知sin(π\4-a)=5\13,0
已知sin(π/4-a)=5/13…
已知sin(45度-a)=5/13,求sin(25pai/4 + a)
已知sin(a-π/4)=-根号2/10,0
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
已知sin a-2cos a=0 求4sin^2 a-3sin a x cos a-5cos^2 a的值
已知sin(a+π/6)=4/5 a∈(0,π/3) 求cosa
已知sin(π/4—a)=5/13,0<a<π/4,则cos2a等于多少?
已知sin[(π/4)-x)]=5/13,0
已知sin(π/4-α)=5/13,0
已知tanb=4/3,sin(a+b)=5/13,a,b∈(0,π),求sina
已知sin(a+x)=4/5,且sinacosa<0,求[2sin(a-π)+3tan(3π-a)]/4cos(a-3π
已知方程sin(a-3π)=2cos(a-4π),求 [sin(π-a)+5cos(2π-a)]/[2sin(3π/2-