sin+x-y

融威怎5095sinx - sina 怎么化成右边的式子的 -
淳丁祝19793784767 ______[答案] 和差化积公式sinx+siny=2sin[(x+y)/2]cos[(x-y)/2]sinx-siny=2cos[(x+y)/2]sin[(x-y)/2]cosx+cosy=2cos[(x+y)/2]cos[(x-y)/2]cosx-cosy=-2sin[(x+y)/2]sin[(x-y)/2]第二个数学辅导团为您解答,满意请点右上角选为满意...

融威怎5095sinx - siny 的复合角公式 -
淳丁祝19793784767 ______[答案] sinx-siny = 2 cos[(x+y)/2]sin[(x-y)/2] 利用两角和公式:sinx-siny=sin[(x+y)/2+(x-y)/2]-sin[(x+y)/2-(x+y)/2]=sin[(x+y)/2]cos[(x-y)/2]+cos[(x+y)/2]sin[(x+y)/2]-{sin[(x+y)/2]cos[(x-y)/2]-cos[(x+y)/2]sin[(...

融威怎5095sin(x+y)sin(x - y)=sin^2x - sin^2y是证明题,写下过程哦,嘿嘿我有点看不懂~~~~~~5555555555 -
淳丁祝19793784767 ______[答案] 本题应用积化和差公式:(先说说公式推导:cos(x+y)=cosxcosy-sinxsiny;cos(x-y)=cosxcosy+sinxsiny;于是sinxsiny=(cos(x-y)-cos(x+y))/2;)将公式应用于本题左边=sin(x+y)sin(x-y)=(cos2y-cos2x)/2=(1-2sin^2y-1+...

融威怎5095化简sin(x+y)sinx+cos(x - y)cosx 怎么化啊 -
淳丁祝19793784767 ______ sin(x+y)sinx+cos(x-y)cosx=(sinxcosy+cosxsiny)sinx+(cosxcosy+sinxsiny)cosx=sin²xcosy+sinxcosxsiny+cos²xcosy+sinxcosxsiny=(sin²x+cos²x)cosy+2sinxcosxsiny=cosy+sin2xsiny

融威怎5095我想知道sin(x+y) - sinx=2siny/2cos(x+y/2),是怎么来的,要详细哦,我在数学方面不好!
淳丁祝19793784767 ______ 角的变化:(x+y+x)/2=x+y/2、(x+y-x)/2=y/2 所以sin(x+y)-sinx=sin[(x+y/2)+y/2]-sin[(x+y/2)-y/2]=[sin(x+y/2)cos(y/2)+cos(x+y/2)sin(y/2)]-[sin(x+y/2)cos(y/2)+cos(x+y/2)sin(y/2)]=2siny/2cos(x+y/2),

融威怎5095sin(x - y)/sin(x+y)=2009/2010,求tanx/tany -
淳丁祝19793784767 ______ sin(x-y)/sin(x+y)=(sinx*cosy-cosx*siny)/(sinx*cosy+cosx*siny) 1tanx/tany=(sinx/cosx)*(siny/cosy)=(sinx*cosy)/(cosx*siny) ...

融威怎5095通过变形把sinx - siny化成三角函数积的形式. -
淳丁祝19793784767 ______[答案] 和差化积 sinX+sinY=2sin[(X+Y)/2]cos[(X-Y)/2];sinX-sinY=2cos[(X+Y)/2]sin[(X-Y)/2]cosX+cosY=2cos[(X+Y)/2]cos[(X-Y)/2]cosX-cosY=-2sin[X+Y)/2]sin[(X-Y)/2]积化和差sinXcosY=1/2[sin(X+Y)+sin(X-Y)]cosXsinY=1...

融威怎5095为什么sin(x+y) - sinx = 2cos(x+y/2)siny/2 -
淳丁祝19793784767 ______[答案] x+y=x+y/2+y/2 x=x+y/2-y/2 sin(x+y)=sin(x+y/2+y/2)=sin(x+y/2)cosy/2+cos(x+y/2)siny/2 sinx=sin(x+y/2)cosy/2-cos(x+y/2)siny/2 所以 sin(x+y) - sinx =sin(x+y/2)cosy/2+cos(x+y/2)siny/2-[sin(x+y/2)cosy/2-cos(x+y/2)siny/2] = 2cos(x+y/2)siny/2

融威怎5095设已知实数x,y满足,xtanx=m,ytany=m,其中m不等于0,xy不相等,,则sin(x+y)/(x+y) + sin(x - y)/(x - y)= -
淳丁祝19793784767 ______ 答案是 0 xtanx=m,ytany=m,所以 x*sinx =mcosx ,y*siny=mcosy sin(x+y)/(x+y) + sin(x-y)/(x-y)=(通分) [sin(x+y)*(x-y) + sin(x-y)*(x+y)] / (x+y)(x-y) = { [sin(x+y)+sin(x-y)]*x - [sin(x+y)-sin(x-y)]*y} / (x+y)(x-y) =(和差化积公式) [2sinxcosy*x-2cosxsiny*y] / (x+y...

融威怎5095题目△y=sin(x+△x) - sinx=2cos (x+△x/2)sin△x/2这个怎么理解详细点 -
淳丁祝19793784767 ______[答案] 利用的是和差化积公式:sin α-sin β=2cos[(α+β)/2]·sin[(α-β)/2] ∴△y=sin(x+△x)-sinx=2cos (x+△x/2)sin△x/2