1/x is undefined when x->0. So the limit could lie anywhere between 1 and -1 since cosine is bounded by those values. Thats what Maple is trying to tell you.

Thanks Robert. I do mean sin(x)/x. What you did up there is really cool. It'll really help me out a lot. I'm taking signal processing and basically need to convert my answers (which are a whole bunch of awful expressions) into sinc functions. All that algebra with trig and Eulerian identities can really drive a person nuts. plus its real easy to make a mistake. Thanks again. I really appreciate your help.

Thanks a lot J. Tarr! First I did: > assign(s); > a, b, c, d; Then I entered the following and maple substituted the constant values. a+b*t+c*t^2+d*exp(-4*t)

I keep mixing my x's and t's... and I never learn. I do it over and over and over again. I'm so mad at myself! But thanks for pointing that out.

I copy and pasted your collect(lside, [sin(8*t), cos(8*t)]); which seemed identical to mine, and it worked! Probably some bug in Maple, no? Anyways, thanks Jacques. You're awesome at Maple.

Thanks Jacques. Its Maple 10 (on campus lab computers). I thought maybe I need to expand the equation. I tried 'expand' but it eliminated the the form I wanted the equation to be in - Turned sin(8t) into some form of sin(t) and did the same to cos(8t): > lside := expand(d2y-12*d1y+101*y(t)); I'm trying to use the method of undetermined coefficients so expand didn't help. Its strange that it doesn't work for me on Maple 10? What output did you get with it?

Aside from the x's and t's mixed... I wrote y as a variable itself without (t). The correct way to write it was y(t)... Sorry, I'm a noob.

Haha... let me check after I spotted this. careless....