Askor explained: I believed trigonometric substitution only operate if there is out there a sq. root for example ##sqrt x^2 + two ##. No. Trig substitution is helpful if you have the sum or distinction of squared terms - they don't need to be inside of a sq. root. Gabletop https://gabletoppak.com/the-growing-threat-of-marine-pollution-and-how-gabletop-cartons-offer-a-solution/