How do i solve all the questions?

Solve the following beat problem for the given initial condition : du ak du dt dna UCM,0) - f (2) u(0,6)=0 ,ULL,t)=0 f (n) = 15 sin (7an A sin ( 20 ) 1) Using separation method Canalytical solution) in using numerical method with 5 iterations Lil An:0.25 At 01 2 K = 0.1 iii) Determine the absolute error at t= 0.5