（x-2y-1)(x-0.5y+1)-(x-0.5y-1)的平方,其中x=1.7 y=3.9

[(-x-y)(-x+y)-(x+y)^2-x(y-y^2)}÷1/2y mathematica软件,已知y[x],Y=f1(x),X(x)=f2(x),如何plot Y[X]?y[x_] := x + 9.81/2*x*xk=1X[x] = x - k*y'[x]/(1 + (y'[x])^2)^0.5Y[x] = y[x] + k/(1 + (y'[x])^2)^0.5Plot[{y[x],Y[X],},{x,0,2}] 1、y-x/x²-y²2、(x-y)(y-z)(z-x)/(z-y)(y-x)(x-z) (x-y)(2x-y-1) (x/x+y-x/y-x-2xy/x.x-y.y)/(1/x-1/y) 分式化简 x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² 2y(x+二分之一y)-[(x+y)(x-y)+2y(y+x)],其中|x-1|=2 （x-y)(x+y)-(x+y)^2+2y(y-x),其中x=1,y=3. (x+y)(x-y)+4(y-1) matlab画二元函数图像z = (x/(x+y) + 1.96*1.96/(2*(x+y)) - 1.96 * ((x/(x+y)*(1-x/(x+y))+1.96*1.96/(4*(x+y)))/(x+y))^0.5)/(1+1.96*1.96/(x+y))该怎么画 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 1/2x=0.5y则y/x()/(). 1/2x=0.5y则y/x()/(). [(-2x-y)^2-(2x+y)(2x-y)]÷2y-1/2y (x-5y)(-x-5y)-(-x-5y)^2其中x=-1,y=-0.5 (x-y/1-x+y/1)÷2y/y-x计算错了，是(1/x-y-1/x+y)÷2y/y-x 求(1+y)-2x(1+y)+x(1-y)