Askor stated: I thought trigonometric substitution only function if there is obtainable a square root like ##sqrt x^2 + 2 ##. No. Trig substitution is useful When you've got the sum or change of squared conditions - they needn't be within a square root. Simple to use, it comes along https://gabletoppak.com/why-paper-water-bottles-are-gaining-popularity-in-kerala/