化简cos(π/4 减a)cos(π/4 加a) 急呀!
sin(π/4-a) cos(a-π/4)化简
化简sin(2π+a)cos(π-a)cos(π/2-a)cos(7π/2-a)/cos(π-a)sin(3π-a)si
计算cos(a+5π/12)cos(a+π/6)+cos(π/12-a)cos(π/3-a)
cos2A+cos(4π/3-2A)化简,
急::已知sin(3π+a)=2cos(a-4π),求(5sin(π/2+a)+cos(π/2-a))/(2cos(π+
化简(2cos^2A-1)/2tan(π/4-A)cos^2(π/4-A)
化简 cot(a+4π)cos(a+π)[sin(a+3π)]^2/tan(π+a)[cos(-π-a)]^2
1-2cos^2(π/4-a/2)
【1】化简:sin(a-5π)/cos(3π-a)×cos(π/2-a)/sin(a-3π)×cos(8π-a)/sin
化简 1-sin^4a-cos^4a/cos^2a-cos^4a
化简(1-sin^6 a-cos^6 a)/(cos^2 a-cos^4 a)==
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