知道cos a=3/4cos(a+阝)=3/5怎么求sin阝
已知(4sin a-2cos a)/(5cos a +3sin a)=6/11,求cos^4 a-sin^4 a
已知sin a-2cos a=0 求4sin^2 a-3sin a x cos a-5cos^2 a的值
已知tan a=-1/3,求4sin a-2cos a/5cos a+3sin a=
已知tan a=2,求:(4*sin a-2*cos a)/(5*sin a+3*cos a)的值
已知sin(a-3π)=2cos(a-4π),求(sin(π-a)+5cos((3π/2)-a))/(2sin(3π/2
已知方程sin(a-3π)=2cos(a-4π),求 [sin(π-a)+5cos(2π-a)]/[2sin(3π/2-
急::已知sin(3π+a)=2cos(a-4π),求(5sin(π/2+a)+cos(π/2-a))/(2cos(π+
cosa-cosβ=4/5 sina-sinβ=3/5 求cos(a-β)
已知sin(派-a)=2cos(派+a),求sin(派-a)+5cos(2派-a)/3cos(派-a)-sin(-a)
已知a是锐角且cos^4a-sin^4a=3/5,求(sin^2a+3sinacosa-cos^2a)/(2sin^2a
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cos(π/2+a)=2sin(a-π/2)求sin(π-a)+cos(a+π)/5cos(5π/2-a)+3sin