化简［sin(2丌-a)-cos(11丌／2-a)］／［sin(-丌-a)sin(9丌／2+a)］

化简Sin A + Sin 2A / 1+cos A + 化简:sin(-a)cos(2π+a)sin(-a-π) 化简sin^2a-cos^2a 化简sin^2a+sin^β-sin^2a*sin^2β+cos^2a*cos^β 化简:sin(3丌-a)/tan(a-5丌)x tan(-a+2丌)/cot(丌-a)x cos(4丌-a)/sin(- 已知 sin a,sin 2x ,cos a 成等差数列,sin a ,sin x ,cos a 成等比数列,求cos 化简 sin(2π-a)sin(π+a)cos-π-a) / sin(3π-a)cos(π-a) 化简：sin(2pi-a)sin(pi+a)cos(-pi-a)/sin(3pi-a)cos(pi-a) sin^2a+sin^2a.cos^2a+cos^2a化简 化简cos^2(a+15)+sin^2(a-15))+sin(a+180)cos(a-180) 化简[cos(a-π)/sin(π-a)]sin(a-π/2)cos(π/2+a)= 化简~cos^2(a+15)+sin^2(a-15)+sin(a+180)cos(a-180)