I'm participating in research this summer and it's has to do with the Fourier Series. My professor wanted to give me practice problems before I actually started on the research. He gave me a square wave and I solved that one without many problems, but this triangle wave is another story. I've been stuck on it for a day or two and wanted to see if I'm even on the right track because I'm very,very lost. Here is the problem: The triangle wave has a period of 4 and starts at (0,0) to (1,1). Then from (1,1) to (3,-1). And then (3,-1) to (4,0). I solved a0 and got 0. Solving for ak is where I'm having a problem. I tried to type the problem out on here but I couldn't get the code to work properly, so instead I took a picture. My question is, did I solve the first one correctly? I didn't solve the (-t+2) or (t-4) integrals yet, just the very first one listed.