u-substitution is an extremely useful technique. Harnessing the power of the chain rule, it allows us to define a new variable (common denoted by the letter u) as a function of x, and obtain a new expression which is (hopefully) easier to integrate.
6121_u_substitution_example_2.html
6125_u_substitution_and_back_substitution.html
6127_Doing_u_substitution_twice.html
6123_u_substitution_with_ln_x_.html
6126_u_substitution_with_exponential_function.html
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