cos(5兀/12+a)=1/3,且-兀
已知cos(a+5π/12)=1/3 且-π
已知cos(5π/12 +a)=1/3 且-π
已知cos(5π/12+a)=1/3,且-π
已知cos(5π/12+a)=1/3,且-《a《-π/2,则cos(π/12—a)等于?
已知角a为钝角,且sin(a+π/12)=1/3,则cos(a+5π/12)=?
已知a(-0,兀且2SIN A-SIN ACOS A-3COS A=0求SIN(+兀/4)/SIN 2A+COS 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
cos(a-阝/2)=-1/9,sin(a/2-阝)=2/3,且兀/2
若cos(π+A)=1/3且0
已知sin(a+b)=-3/5,cos(a-b)=12/13,且π/2
已知a为第三象限角,且f(a)=sin(5π-a)cos(a+3π/2)cos(π+a)/sin(a-3π/2)cos(
已知x为锐角且cos=1/3,求tan a+cos a/(1+sin a)