Another question from **O Level Additional Mathematics (A-Math)**.

lijun(: said...

i came across this qu that day, and i really want to clarify if the method i used is correct or not.int(tan^2x - x^3)

i changed it to int(sec^2x - 1 - x^3) instead, cos i don't think we can integrate tan.

is that feasible?

Absolutely. Since tan^2 x can't be integrated, you must think of alternative by making use of the relationship of tan^2 x + 1 = sec^2 x

LinwooD says

yes, it's feasible. we dont learn how to integrate tan so we have to change it to sec^2x - 1. great attempt :)