i did some steps but im not sure if i did it right
pls help
integral sinx+secx(cotx) dx
integral sinx+1/cosx(cosx/sinx) = so cosx cancel each other= integral sinx+cscx
Three answers:
Kathleen K
2013-06-27 17:35:58 UTC
ʃ (sinx + secx) / tanx dx
= ʃsinx/tanx + secx/tanx dx
= ʃcosx + cscx dx
= sinx - ln |cscx+cotx| + c
Please note: ʃcscx dx = -ln|cscx+cotx|. There is a top secret (!) way to derive this integration formula, and that is to multiply ʃcscx dx by (cscx + cotx)/(cscx + cotx) to get ʃ(csc²x + cscxcotx) / (cscx + cotx) dx, which is ʃ-du/u when letting u = cscx + cotx. That blew my mind when I first learned it!