Mathematics
OpenStudy (anonymous):

How do you find the lim (-7x^2-8y^2)/(sqrt(-7x^2-8y^2+1)-1) (x,y)->(0,0)? The hint is to rationalize the denominator but I have tried this and it only seems to make things complicated.

OpenStudy (anonymous):

Multiple numerator and denominator by conjugate. I'll work it out now.

OpenStudy (anonymous):

I tried that but it made things complicated because of the -1. Did I do something wrong?

OpenStudy (anonymous):

I got...$\sqrt{1}+1$

OpenStudy (anonymous):

2

OpenStudy (anonymous):

:)

OpenStudy (anonymous):

Perfect!

OpenStudy (anonymous):

ur left with sqrt(-7x^2 - 8x^2 + 1) + 1 , so solving for the limit yields 2