2.I.1B

Differential Equations
Part IA, 2001

Find the solution to

dy(x)dx+tanh(x)y(x)=H(x)\frac{d y(x)}{d x}+\tanh (x) y(x)=H(x)

in the range <x<-\infty<x<\infty subject to y(0)=1y(0)=1, where H(x)H(x) is the Heavyside function defined by

H(x)={0x<01x>0H(x)= \begin{cases}0 & x<0 \\ 1 & x>0\end{cases}

Sketch the solution.