y={x+1,x≤0；x-1,x＞0}有零点吗

y={x+1,x≤0；x-1,x＞0}有零点吗 作函数y= x (x>0) 1 (-1≤x≤1) -2x (x 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}] 数学不等式：变量x,y满足约束条件「x-y≥0,x+y≤0,x+2y≥1」,求z=5x+y的最大值变量x,y满足约束条件「x-y≥0,x+y≤0,x+2y≥1」,求z=5x+y的最大值,有图最好!变量x,y满足约束条件「x-y≥0,x+y≤1,x+2y≥1」， 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 y=1-x^2 x>=0 ,y=sin|x|/x x 设函数f(x)的定义域为R,且f(x)不等于0,当x>0,f(x)>1,对x,y属于R,有f(x+y)=f(x)f(y).设函数f(x)的定义域为R,且f(x)不等于0,当x>0时,f(x)>1,对x,y属于R,有f(x+y)=f(x)f(y).（1）求证：f9x)>0（2）解不等式 f(x)≤ 1/f(x+1 y=1/x^2(x>0) y=(1-x)/(1+x) y=(e^x-e^-x)/2 若x+y=1,x不等于0则x+(2xy+y^2)/x/(x+y)/x= ①y=x²+2x-3 X∈（0,1）②y=x²+2x-3 X∈（2,3）③y=x²+2x-3 X∈（-2,0）④y=2/x 1＜x≤2⑤y=3/x-1 X＞1⑥y=3/x-1 +1 X＞1⑦y=-（x-3）*丨x丨 x=0:10; y=2*x^2+3*x+1; plot(x,y) 提示y=2*x^2+3*x+1;这一行有错误 y=x(1-x) (0 设x大于1,y大于0,x^y+x^-y=2根号二,x^y-x^-y等于? 若实数x,y满足x-y+1》=0,x+y>=0,x 已知x,y满足约束条件：x-y+1>=0,x+y-2>=0,x 若实数x,y满足x-y+1>=0,x+y>=0,x 已知函数f(x)满足：对任意x,y属于R 都有f(x+y)=f(x)f(y)-f(x)-f(y)已知函数f(x)满足：对任意x,y属于R 都有f(x+y)=f(x)f(y)-f(x)-f(y)+2成立,且x＞0时,f(x)>2(1)求f(0)的值,并证明：当x＜0时,1＜f(x) 画出不等式组x+y>0,x=还有不等式（x-y)(x-y-1)=