Askor explained: I thought trigonometric substitution only operate if there is accessible a sq. root such as ##sqrt x^2 + two ##. No. Trig substitution is useful For those who have the sum or change of squared terms - they need not be inside of a square root. Front Gable: https://gabletoppak.com/free-water-advertising-a-sustainable-and-emotional-path-to-powerful-brand-recognition/