Askor reported: I thought trigonometric substitution only get the job done if there is obtainable a sq. root for example ##sqrt x^2 + 2 ##. No. Trig substitution is helpful if you have the sum or variation of squared conditions - they don't need to be inside a square root. https://gabletoppak.com/eco-friendly-packaging-solutions-for-dairy-products-in-india/