I don't understand the last 4 steps. Can you please explain it to me. Thank you Get live help whenever you need from online tutors! Try bartleby tutor today →For n = 1, 2, 3, ... so, by Fourier...

I don't understand the last 4 steps. Can you please explain it to me. Thank you

Extracted text: Safari File Edit View History Bookmarks Window Help Mon 9:15 PM A bartleby.com Install SimUText = bartleby Search for textbooks, step-by-step explanations to homework . Ask an Expert Install SimUText E Bundle: Differential Equations with Bou... < chapter="" 12.3,="" problem="" 3e=""> Get live help whenever you need from online tutors! Try bartleby tutor today → For n = 1, 2, 3, ... so, by Fourier cosine series -kn?2 и (х, 1) %3D Ane cos 4x Feb 18, 2021 at 11-18 P...pnglmage n=0 Put t = 0 in above equation, 00 u (x, 0) = f (x) = Ao + 2 An sin " x n=1 Where L. xdx An = | f (x) cos L For n = 1,2, 3, ... so that 00 пл - xdx|e L cos Tx X GET 10 FREE QUESTIONS и (х, t) — f f (x) cos n=1 Privacy - Terms 4 29 étv N ( O