Question 163873
Look for regions where the function is not defined. 
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Examples : 
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Square root arguments become negative
{{{sqrt(x-2)}}}, undefined when x<2, range of x is {{{x>=2}}}
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Denominators go to zero. 
{{{f(x)=5/(x-1)}}}, undefined when x=1, range of x is ({{{-infinity}}},{{{1}}})U({{{1}}},{{{infinity}}})
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