Finding the domain of a function?

Say you were finding the domain of a function with a square root in the denominator. You would set it >=0 correct? but since you look at the denominator to find the domain of a function cant we just make it >0? im confused as to why we use >=0

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  • TomV
    Lv 7
    1 month ago

    If the square root is in the denominator of a rational function, the value of the expression under the radical must be greater than zero for the function to be defined and real valued. In that case, you would not use ≥ 0 because if it were 0, the function would be undefined because of division by zero.

    If the square root is not in the denominator, than you can use ≥ 0 because a zero value for the square root would not be a division by zero.

    So, it depends on whether the square root is in the numerator, in which case the radicand must be ≥ 0, or in the denominator in which case the radicand cannot be zero but must be > 0.

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  • D g
    Lv 7
    1 month ago

    generally  a root has to have a positive numbber inside the sqrt sign

    if on the bottom  of a fraction  the number  cannot be zero

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