A y(t) = c1e 2t cos t + c2e 2t sin t. C y(t) = c1e4t + c2e 5t y(t) = e2t(cid:18) t3. Q#:5 yp(t) = at cos 3t + bt sin 3t + ctet + det + et2 + f t + g y(t) = A the critical points are p = (2, 2) and q = ( 2, 2). B: point p: x = (cid:20)0, point q: x = (cid:20) 0. 4 4(cid:21) x. 1 = 2 + 2 2 and 2 = 2 2 2. 1: point p is a saddle point, which is unstable, point q is an improper stable node, which is stable. u(x, t) = exp[ 9 2t. ] sin = f rac2 x5 2 exp[ 9 2t] sin x + 13 exp[ 19(49) 2t. B the even fourier series is f (x) = ao.
