:求证:(cos^2x-sin^2x)(cos^4x+sin^4x)+1/4sin2xsin4x=cos2x
求证:(cos^2x-sin^2x)(cos^4x+sin^4x)+1/4sin2xsin4x=cos2x
我算到右边=cos2x(1-sin^2xcos^2x) 接下来该怎么办?
人气:309 ℃ 时间:2019-10-31 12:04:46
解答
不知道你怎么算的
左边=cos2x[(sin²x+cos²x)²-2sin²xcos²x]+1/4sin2x*2sin2xcos2x
=cos2x[1-1/2*(2sinxcosx)²]+1/2sin²2xcos2x
=cos2x-1/2*sin²2xcos2x+1/2sin²2xcos2x
=cos2x
推荐
- 求证(cos^2x-sin^2x)(cos^4x+sin^4x)+1/4sin2xsin4x=cos2x
- 求证!cos^8x-sin^8x+1/4sin2xsin4x =cos2x
- 求函数y=sin^4 x-cos^4x 最小正周期?化简:sin^2x-cos^2x=1-2cos^2x=- cos2x .T=2π//2=π
- 如果cos2x=a,那么sin^4x+cos^4x的值等于?
- 若cos2x=√2/3,则cos^4x+sin^4x=多少?
- 在一次旅途中,有一批游客过一条河,如果每只船坐10人,那么剩4人;如果每只船坐12人,那么还剩1只船,则船有多少只?这批游客有多少人?(列方程解答)
- 工程队修路,第一天修全长的1/8多16千米,第二天修全长的1/6少2千米,剩下88千米,这条路多长
- 12.Would the girl you were be happy about the woman that you have become?英译汉,
猜你喜欢