 so far can come in various shapes. Now if you square this out, if you square it up, 1 plus 2 sin x cos x is equal to t square minus cos x term would be t square, so which becomes minus 1 by t, cos x plus 2 sin x cos x. Here itself we can end it unnecessarily. This one? No we don't. 1 by k, any person close to the tree? Most of you are sitting on this next question. So your d x term will become cos x square, what is cos x square? 1 plus 4 square which is 1 plus, the benefit is this will become.