$(a)$ What $is$ the condition for the maximum velocity $in$ terms $of$ the change $inu$ with respect $toy?$

$(b)$ What $is$ the expression for $\frac{d(\frac{u}{U})}{d(\frac{y}{b})}?$ What $is$ the expression for $\frac{y}{b}in$ terms $ofPat$ the maximum velocity?

$(c)$ What $is$ the value $of\frac{y}{b}at$ the maximum velocity?

$(a)\frac{du}{dy}=$

$(b)$

$\frac{d(\frac{u}{U})}{d(\frac{y}{b})}=-P(2\frac{y}{b}-1)-1$ and $\frac{y}{b}=\frac{1}{2}-\frac{1}{2P}$

$\frac{d(\frac{u}{U})}{d(\frac{y}{b})}=-P((\frac{y}{b}{)}^2-\frac{y}{b})-1$ and $\frac{y}{b}=\frac{1}{2}-\frac{1}{2P}$

$\frac{d(\frac{u}{U})}{d(\frac{y}{b})}=-P(\frac{y}{b}-1)+1$ and $\frac{y}{b}=\frac{1}{2}-\frac{1}{P}$

$\frac{d(\frac{u}{U})}{d(\frac{y}{b})}=-P(2\frac{y}{b}-1)$ and $\frac{y}{b}=1-\frac{1}{2P}$

$(c)\frac{y}{b}=$

Can you please help $me$ figure this out. I $am$ confused $on$ what I $am$ doing wrong.