if the paper says: Domain = reals, then isn't the range also {y: y= reals}?

thanks

please! this is urgent

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- Oct 9th 2007, 05:05 PMkrutondomain and range question
if the paper says: Domain = reals, then isn't the range also {y: y= reals}?

thanks

please! this is urgent - Oct 9th 2007, 05:09 PMJhevon
no. it depends on the question. the domain and the range are two different things, they are not always equal.

for instance, for $\displaystyle y = x^2$, the domain is all real x, but the range is all real y that are greater than or equal to zero. so $\displaystyle dom(y) = ( -\infty, \infty)$ and $\displaystyle ran(y) = [0, \infty)$ - Oct 9th 2007, 05:11 PMkruton
the function is y=-5-2X

domain = reals

range = y greater than or equal to 0

is that right?

but why can't y be less than zero? - Oct 9th 2007, 05:14 PMJhevon