Plot of Quadratic Equation coming out Linear...What do I do??? Emergency

Here is my plot code

clear all

x=[-10:1:10];

y1=-x+x.^2/(1+x.^2);

y2=-.5*x + x.^2/(1+x.^2);

y3=-.2*x+x.^2/(1+x.^2);

plot(x,y1,'r',x,y2,'b',x,y3,'g')

It should look like three different versions of a differential curve with increasing parameter values, but all three plots come out linear. Looks correct on another graphing site. What am I doing wrong?

Answer 1

[Roger Stafford]

Try putting a dot on your division symbols:

 y1=-x+x.^2./(1+x.^2);

As you have it the division is matlab's matrix division which in this case gives a scalar value, hence the linear appearance.

See

 http://www.mathworks.com/help/matlab/ref/mrdivide.html