y=2x-1,y=x 2绕x轴旋转体的体积
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x²-2xy+y²-x+y-1=0(x-y)²-(x-y)-1=0[x-y-(1+√5)/2][x-y-(1-√5)/2]所以x-y=(1+√5)/2或x-y=(1-√5
解题思路:由完全平方公式可求解题过程:varSWOC={};SWOC.tip=false;try{SWOCX2.OpenFile("http://dayi.prcedu.com/include/rea
去分母得:x^2(y-1)+x(1-y)+y=0y=1时,上式无解y=1时,为二次式,须有delta>=0即(1-y)^2-4y(y-1)>=0(y-1)(3y+1)再问:x^2(y-1)+x(1-y
#includemain(){intx,y;charch='*';printf("输入x的值:");scanf("%d",&x);if(x>0){y=x+1;}elseif(x
x²+(2-y)x+y²-y+1=0方程有解的条件是:△=b²-4ac≥0→-3y²≥0∴y=0∴x=-1
y=x2+2x+1/(x2+2x+3)=(x+1)2/(x2+2x+3)当分母一定时,分子越小越好(x2+2x+3)=(x+1)2+2永远大于零当(x+1)2越小越好而X=-1时y=x2+2x+1/(
[(x^2+y^2)-(x-y)^2+2y(x-y)]÷4y=1(x^2+y^2-x^2+2xy-y^2+2xy-2y^2)÷4y=1(4xy-2y^2)4y=12x-y=24x/(4x^2-y^2)
先画出y=x^2-2x的图像,然后把在x轴下方翻折到上面,然后总体向上平移一个单位由于不方便所以只能告诉你方法再问:y=x^2-2x用不用考虑两种情况?再答:不用,那样会很麻烦
就把(x2+1/x)=y代进去(2(x2+1)/x)+(6x/x2+1)=7化为2y+6/y=7解之得y=3/2或2(x2+1/x)=3/2时无解(x2+1/x)=2时x=1再问:用换元法把(x2+1
x^2+(2-y)x+y^2-y+1=0这个关于x的二次方程有解b^2-4ac>0-3y^2>0所以y=0x=-1
(X+Y)²=X²+Y²+2XY=X²+Y²+X²-Y²=2X²(X-Y)²=X²+Y²-
解析:y′=8x-1x2=8x3−1x2,令y′>0,解得x>12,则函数的单调递增区间为(12,+∞).故答案:(12,+∞).
由题意作出如下图形:令k=y−(−2)x−(−1),则k可看作圆x2+y2=1上的动点P到定点A(-1,-2)的连线的斜率而相切时的斜率,由于此时直线与圆相切,设直线方程为:y+2=k(x+1),化为
y=(x^2-2x-3)/2x^2+2x+1,x^2-2x-3=2yx^2+2yx+y(2y-1)x^2+(2y+2)x+y+3=0(2y+2)^2-4(2y-1)(y+3)>=0-4=
不对=x2(x-y)-y2(x-y)=(x2-y2)(x-y)=(x+y)(x-y)2再问:噢。我看懂了
哥!你那个是x方y方吧!有这么个公式x方-y方=(x+y)(x-y)所以得到了(x+y)(x-y)-(x+y)这时候提取公因式(x+y)就得到了(x+y)(x-y-1)再问:是啊,怎么提(X+Y)他那
因为(x+y)(x+y+1)=0所以x+y=0,或x+y=-1,x2+y2+2xy=(x+y)²当x+y=0时,原式=0,当x+y=-1时,原式=1
(x-y)/(x+y)=(x-y)(x+y)/[(x+y)^2]=(x^2-y^2)/[x^2+y^2+2xy]=2xy/[x^2+y^2+x^2-y^2]=2xy/(2x^2)=y/xx^2-y^2