化简sin^2Xsin^2Y+cos^2Xcos^2Y-0.5cos2Xcos2Y

来源：学生作业帮编辑：百度作业网作业帮分类：数学作业时间：2024/06/17 09:02:11

(sinx)^2(siny)^2+(cosx)^2(cosy)^2-1/2*cos2xcos2y
=(1-cos2x)/2*(1-cos2y)/2+(1+cos2x)/2*(1+cos2y)/2-1/2*cos2xcos2y
=(1-cos2x-cos2y+cos2xcos2y)/4+(1+cos2x+cos2y+cos2xcos2y)/4-1/2*cos2xcos2y
=(1+cos2xcos2y)/2-1/2*cos2xcos2y
=1/2
再问： 2sinX-cosX=1求sinX+conX+1/sinX-cosX+1
再答：两端平方 4(sinx)^2-4sinxcosx+(cosx)^2=(sinx)^2+(cosx)^2 3(sinx)^2=4sinxcosx 1)sinx=0，则cosx=-1，代入得 0 2)sinx不为0，则 3sinx=4cosx，sinx=4/3*cosx，代入已知等式得 cosx=3/5，sinx=4/5 代入得 2 0或2

求证 cos*xcos*y + sin*xsin*y + sin*xcos*y + xin*ycos*x = 1 (2xsin(y/x)-ycos(y/x))dx+(xcos(y/x)+1)dy=0 求y 求函数y=2sin xcos x+2sin x+2cos x+4的值域化简sin(2x-y)*sin y+cos(2x-y)*sin y 求函数y=sin^4x+cos^4x+4sin^2xcos^2x-1的最小正周期和值域求函数y=sin^4x+cos^4x+4sin^2xcos^2x-1的最小正周期值域化简cos^4x+sin^2xcos^2x+sin^2x 题目是y=sin平方x乘以cos平方x,进行求导,正确答案是sin2xcosx^2-2xsin平方xsinx^2,我想知 sin^2x+cos^2x)(sin^4x-sin^2xcos^2x+cos^4x) =sin^4x-sin^2xcos 已知圆M:(x+cosθ)^2+(y-sinθ)^2=1,直线l:xcosθ-ysinθ+k=0,则下面四个命题: 求曲线x^2-6xcosθ-4y+9cos^2θ+8sinθ=0(θ为参数)的焦点轨迹方程已知fx=cos二分之πxcos二分之x-sin二分之三xsin二分之x-2sinxcosx,当x属于二分之π,π时,f