x^2+y^2-2x-2y+1=0 ,x+y-k大于等于0,求k的取值范围.(用三角代换解）如果有简单的方法更好x^2+y^2-2x-2y+1=0 ,x+y-k大于等于0,求k的取值范围.(用三角代换解）如果有简单的方法更好

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 设x大于1,y大于0,x^y+x^-y=2根号二,x^y-x^-y等于? 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}] 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 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. 已知x,y满足约束条件：x-y+1>=0,x+y-2>=0,x 化简y(x+y)+(x+y)(x-y)-x^2 因式分解x(x+y)(x-y)-x(x+y)^2 [(-x-y)(-x+y)-(x+y)^2-x(y-y^2)}÷1/2y y=1/x^2(x>0) y=(1-x)/(1+x) y=(e^x-e^-x)/2 若|x+y-1|+（x-y-2)²=0,求代数式（x+2y)(x-2y）-（2x-y)(-y-2x)的值. 若x+y=1,x不等于0则x+(2xy+y^2)/x/(x+y)/x= 已知x^2+y^2-8x+12y+52=0 ,求1/2x-1/x-y(x-y/2x-x^2+y^2) 已知x^2+y^2-8x+12y+52=0 ,求1/2x-1/x-y(x-y/2x-x^2+y^2) y=1-x^2 x>=0 ,y=sin|x|/x x 已知x>0,Y>0,如何证x^2/y+y^2/x>=x+y