#$4$ Consider the second order difference equation with constant coefficients

$py(t+2)-y(t+1)+qy(t)=0,y(0)=0,y(l)=1,.$

Suppose $p+q-1.$

a$)$ Find the solution of Eqn. $(1).$

b$)$ Find

$\underset{t}{lim}y(t),if\frac{q}{p}<mn>1</mn>$

c$)$

$\underset{t}{lim}y(t),if\frac{q}{p}>1$