Find the Y-parameters for the following two-port circuit

[ongxom]

Homework Statement

Find the Y-parameters for the following two-port circuit

Homework Equations

The Attempt at a Solution

Node 1 :V₁(1/3+1/4)-1/4V₂=I₁
Node 2 : -1/4V1 + V₂(1/4+1/5)-1/5(2I₁)=I₂

Subtitute I1 from the first equation to second equation, we have :
I1=7/12V1-1/4V₂
I2=-29/60V₁+11/20V₂

So y₁₁=7/12, y12=-1/4, y21=-29/60, y₂₂=11/20

But the solution gives me that y₁₂=1/4 and y₂₁=29/60, there are differences of signs. I haven't found my mistake.

 

[gneill]

Could be you haven't made a mistake! Your results look okay to me.

 

[rude man]

Your answer is correct. The "solution" is wrong.