How do i input (-1/x) - (y^2/x^2) into Matlab?

 So far i've tried these:

(-1./X) -(Y.^2 * X.^-2)

(-X.^-1) -(Y.^2 * X.^-2)

(-X.^-1) -(Y.^2 / X.^-2)

(-X.^-1) -((Y.^2). / X.^-2)

(-X.^-1) -((Y.^2). / (X.^-2)))

can someone tell me what i am doing wrong?

Answer 1

[Paul Graham]

(-1./x) - (y.^2./x.^2)

Answer 2

[Star Strider]

Use the original equation with element-wise operations (note the dot operator ‘.’ before the exponentiation and division operators):

Z = (-1./X) - (Y.^2./Y.^2);

See the documentation for Array vs. Matrix Operations for details. (You would also use the dot operator with the multiplication operator if you used it here: (.*).)

Then use the meshgrid function to create compatible matrices for your variables:

x = linspace(-5, 5,25);
y = linspace(-10, 10, 50);
[X,Y] = meshgrid(x,y);

Use the surf or mesh functions to plot it.

I leave the rest to you.