1. The problem statement, all variables and given/known data Solve d2θ/dη2 + 2η(dθ/dη) = 0, to obtain θ as a function of η, where θ=(T-T0)/(Ts-T0) EDIT: I should add that this is a multi-part problem, and η is given as η=Cxtm. We had to use that to derive the equation in question above.. So I dont know if this is supposed to be solved as a non-constant coefficient method or not... My method below solved it assuming η was a constant.. I can supply the whole problem as an attachment if necessary. 2. Relevant equations ay"+by'+cy=0 ar2+br+c=0 If the roots are real and different, solution is: y=aer1x+ber2x 3. The attempt at a solution I would assume this can just be: θ"+2ηθ'=0 which turns to: r2+2ηr=0 But when using the quadratic equation to get roots, I get r1=-2η, and r2=0 Plug this into the solution form and get θ=ae-2ηx Not sure if this is right. Can someone confirm, or tell me what I'm doing wrong? Thanks!