Method of replacement of variables - one of remarkable methods of the solution of mathematical tasks. Often successful replacement of a variable helps to simplify considerably the decision, and sometimes is the only way to come to the answer.
Instruction
1. Think what replacement of variables can be made and as it will help to solve a problem. Try various options. Perhaps, replacement will help you to get rid of roots or big degrees; can be, will present the equation in the form, more convenient for the decision.
2. Specify your replacement by a variable, beginning with the words ""let"", let's ""replace"", ""let's enter replacement"". Enter designation for new size. Set restrictions for this size. For example, if you replace x^2 with t, surely specify that t has to be non-negative number. If you replace 1/x with t, note that t cannot equal to zero.
3. Find value of your new variable from the equation.
4. Look whether everything the received values meet requirements to this variable. Eliminate superfluous.
5. Return to old variables, having substituted the found values instead of replacement.
6. Replacement of variables can be done several times. Only do not forget to come back to those variables which you replaced.