In what situation do we need to use substitution rule? what is the purpose for using substitution rule?

Substitution rule is one of the most important rule to solve the integrals problem.

In substitution rule we substitute  different  variable in such a way that it can simplify the question.

example: when we have to solve "Sin x²" we cannot solve it but

               if question is "x  Sin x²" we can substitute x² with t and can solve it.

The purpose of substitution rule is to simplify the problem of integrals.

on monday rodney ate 1/4th of the sandwich = 3/12

on tuesday he ate 1/3rd of the sandwich = 4/12

therefore in total he has eaten = 3/12 + 4/12 = 7/12

thus we can say that he has eaten 7/12 of the sandwich on monday and tuesday alltogether.

happy to

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