化简：cos(π/4-x)乘cos(π/4+x)

化简：cos(π/4-x)乘cos(π/4+x) 化简cos(π/6+x)+cos(π/6-x) cos(-x-2π) 和cos(π-x) 化简 根号2cos(x-π/4)化简 化简1+sin x/cos x·sin2x/2cos²（π/4-x/2） 化简cos[(4n+1)π/4+x]+cos[(4n-1)π/4+x] 由cos(a+b)=cos a cos b-sin a sin b cos(a-b)=cos a cos b+sin a sin b解题设a为锐角,证：1、2分之根3乘cos a + 2分之1乘sin a=cos(6分之π-a)2、cos a-sin a=根号2cos(4分之π+a) 化简sin(3π-x)cos(x-3/2)cos(4π-x)/tan(x-5π)cos(π/2+x)sin(x-5/2π) 化简sin(3π-x)cos(x-3/2)cos(4π-x)/tan(x-5π)cos(π/2+x)sin(x-5/2π) 已知f(x)=sin(π/6-x)^2-cos(π/4+x)^2+cos(π/6)cos(π/6-2x)化简f(x) cos(-π/4)乘tan(-5π/6)=? 证明cos³a＋sin³a+cos四次方a-sin四次方a = 4乘根号2乘cos（π/4-a)乘（π/4-a/2）乘cos²a/2 化简sin(x-π/4)+cos(x+π/4) cos(x+π/4)+sin(x+π/4)化简 化简cos(π/4-a)cos(π/4+a) 化简cos(π/4-a)cos(π/4+a)= 化简sin2x-cos(2x+π/6) （1）化简:根号2sin(π/4-x)+根号6cos(π/4-x)（2）sin(67°-x)cos(x-22°)+cos(67°-x)cos(112°-x)的值为