Help with solving an equation

I am getting an error while trying to solve the below equation (Function value at interval endpoints must differ in sign)

Any idea how to solve it

upCOX = 125;
vtp = -0.15;
lambda = -0.01;
l = 1;
we = 1;
Rload = 10000;
vdd = 1;
va = 0.2;
vgs = va - vy;

        eq1 = @(vy) - 1 + vy + Rload*((upCOX*(we/l)*(1-vy*lambda)*(((vgs-vtp)*(-vy))-(0.5*(vy)^2))));
        x1 = [0 1];
        vy = fzero(eq1,x1);
        disp(vy)

Answer 1

[Sam Chak]

Hi @Amy Topaz

Make a direct substitution of vgs into the equation.

upCOX = 125;
vtp = -0.15;
lambda = -0.01;
l = 1;
we = 1;
Rload = 10000;
vdd = 1;
va = 0.2;
% vgs = va - vy;

        eq1 = @(vy) - 1 + vy + Rload*((upCOX*(we/l)*(1 - vy*lambda)*((((va - vy) - vtp)*(- vy)) - (0.5*(vy)^2))));
        x1 = [0 1];
        vy = fzero(eq1, x1);
        disp(vy)

Hope it helps.

[Amy Topaz]

thanks