Askor claimed: I assumed trigonometric substitution only perform if there is out there a square root for example ##sqrt x^two + 2 ##. No. Trig substitution is helpful For those who have the sum or distinction of squared phrases - they don't need to be inside of a sq. root. https://gabletoppak.com/bioplastics-greenwashing-or-genuine-solution-the-truth-behind-the-hype/