Askor said: I assumed trigonometric substitution only operate if there is obtainable a sq. root for example ##sqrt x^two + two ##. No. Trig substitution is helpful if you have the sum or variance of squared terms - they need not be inside of a square root. The posting traces https://gabletoppak.com/water-in-a-sustainable-box-the-future-of-eco-friendly-hydration/