Askor stated: I believed trigonometric substitution only get the job done if there is obtainable a sq. root like ##sqrt x^2 + 2 ##. No. Trig substitution is helpful if you have the sum or distinction of squared terms - they don't need to be within a square root. This https://gabletoppak.com/choosing-between-gable-top-packaging-and-plastic-bottles-for-your-beverage-business/