MOS differential pair

[STOIKOV]

I'm trying to deduce the differential output current of a MOS differential pair, but have doubt in one step (showed in the picture).

Could please give me some advise ? Thanks.

 

[wpchan05]

By solving the quadratic equation in which Id1 is the only variable, you can get the result.

 

[STOIKOV]

ok thanks, now already got ID by hand with general quadratic formula.

How can a variable be found in matlab by just intoducing the coefficients a,b,c of a quadratic equation, like this equation ?

 

[drabos]

for example:
a=(a number); b=(a number); c=(a number);
y=roots([a b c])

or y(1)=(-b+sqrt(b^2-4*a*c))/(2*a);
y(2)=(-b-sqrt(b^2-4*a*c))/(2*a);

As you wish