Paper 3, Section I, A

Methods
Part IB, 2018

(a) Determine the Green's function G(x;ξ)G(x ; \xi) satisfying

G4G+4G=δ(xξ),G^{\prime \prime}-4 G^{\prime}+4 G=\delta(x-\xi),

with G(0;ξ)=G(1;ξ)=0G(0 ; \xi)=G(1 ; \xi)=0. Here ' denotes differentiation with respect to xx.

(b) Using the Green's function, solve

y4y+4y=e2xy^{\prime \prime}-4 y^{\prime}+4 y=e^{2 x}

with y(0)=y(1)=0y(0)=y(1)=0.