Edexcel M5 2012 June — Question 1

Exam BoardEdexcel
ModuleM5 (Mechanics 5)
Year2012
SessionJune
TopicFirst order differential equations (integrating factor)

  1. A particle \(P\) moves in a plane such that its position vector \(\mathbf { r }\) metres at time \(t\) seconds \(( t > 0 )\) satisfies the differential equation
$$\frac { \mathrm { d } \mathbf { r } } { \mathrm {~d} t } - \frac { 2 } { t } \mathbf { r } = 4 \mathbf { i }$$ When \(t = 1\), the particle is at the point with position vector \(( \mathbf { i } + \mathbf { j } ) \mathrm { m }\).
Find \(\mathbf { r }\) in terms of \(t\).