Calculus Methods

01 Finding Domains

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         1)  Rewrite function as a single fraction, and factor the denominator.

 

         2)  There are only three rules:

 

                  A)  No negative numbers are allowed inside square roots.

 

                  B)  No zeroes are allowed in the denominator.

 

                  C)  No non-positive numbers are allowed inside logs.

 

         3)  Write separate domains for each item involved in the function.

 

         4)  Combine the separate domains using "and."

 

 

 

 

         Example:  Find the domain of

 

        

 

         1)    

 

 

         2A)  There is only one square root (it occurs twice):

                                            

 

         2B)  There are two factors in the denominator:

                                            

 

         2C)  There is one logarithm:

                                   

 

 

         3)  The four domains for this example problem are thus:

                                   

 

    4)  The single domain that is commensurate with all of

    the above domains is (it might help to draw a number

    line):

 
 


         Domain:          

 

         Or in interval notation: 

 

On to Method 02 - Solving Polynomial Inequalities

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