Given that $$x ^ { 2 } \frac { \mathrm {~d} ^ { 2 } y } { \mathrm {~d} x ^ { 2 } } + 4 x ( 1 + x ) \frac { \mathrm { d } y } { \mathrm {~d} x } + 2 \left( 1 + 4 x + 2 x ^ { 2 } \right) y = 8 x ^ { 2 }$$ and that \(x ^ { 2 } y = z\), show that $$\frac { \mathrm { d } ^ { 2 } z } { \mathrm {~d} x ^ { 2 } } + 4 \frac { \mathrm {~d} z } { \mathrm {~d} x } + 4 z = 8 x ^ { 2 }$$ Find the general solution for \(y\) in terms of \(x\). Describe the behaviour of \(y\) as \(x \rightarrow \infty\).

Given that

$$x ^ { 2 } \frac { \mathrm {~d} ^ { 2 } y } { \mathrm {~d} x ^ { 2 } } + 4 x ( 1 + x ) \frac { \mathrm { d } y } { \mathrm {~d} x } + 2 \left( 1 + 4 x + 2 x ^ { 2 } \right) y = 8 x ^ { 2 }$$

and that $x ^ { 2 } y = z$, show that

$$\frac { \mathrm { d } ^ { 2 } z } { \mathrm {~d} x ^ { 2 } } + 4 \frac { \mathrm {~d} z } { \mathrm {~d} x } + 4 z = 8 x ^ { 2 }$$

Find the general solution for $y$ in terms of $x$.

Describe the behaviour of $y$ as $x \rightarrow \infty$.

\hfill \mbox{\textit{CAIE FP1 2011 Q11 OR}}