Askor explained: I assumed trigonometric substitution only perform if there is obtainable a sq. root like ##sqrt x^two + two ##. No. Trig substitution is useful Should you have the sum or variation of squared terms - they don't need to be inside of a square root. The article traces https://gabletoppak.com/water-in-a-sustainable-box-the-future-of-eco-friendly-hydration/