How do you know when theres restrictions on the domain or range ?

Question

aum · Answer

Problems will state the restrictions on the domain.
If not explicitly given you can look for a few things.
If it is a rational function, where there is a polynomial in the numerator and the denominator, then the denominator cannot be zero.  So all the values that causes the denominator to go to zero are excluded from the domain.  
You cannot take the square root of a negative.  So any x value that will make the expression inside the square root negative are excluded from the domain.
Trig functions such as tan has several values of x that will make it undefined and those x values are not allowed in the domain.
You can't take log of a number <= 0.
etc. etc.

anonymous · Answer

Thank Youu ((:  you rock !! @aum

aum · Answer

You are welcome.