| Exam Board | CAIE |
| Module | FP1 (Further Pure Mathematics 1) |
| Year | 2011 |
| Session | June |
| Topic | Second order differential equations |
7 The variables \(x\) and \(y\) are related by the differential equation
$$y ^ { 2 } \frac { \mathrm {~d} ^ { 2 } y } { \mathrm {~d} x ^ { 2 } } + 2 y ^ { 2 } \frac { \mathrm {~d} y } { \mathrm {~d} x } + 2 y \left( \frac { \mathrm {~d} y } { \mathrm {~d} x } \right) ^ { 2 } - 5 y ^ { 3 } = 8 \mathrm { e } ^ { - x }$$
Given that \(v = y ^ { 3 }\), show that
$$\frac { \mathrm { d } ^ { 2 } v } { \mathrm {~d} x ^ { 2 } } + 2 \frac { \mathrm {~d} v } { \mathrm {~d} x } - 15 v = 24 \mathrm { e } ^ { - x }$$
Hence find the general solution for \(y\) in terms of \(x\).