## MTALHAHASSAN2 one year ago Evaluate the limit bu using a change of variable.

1. MTALHAHASSAN2

|dw:1442757977668:dw|

2. MTALHAHASSAN2

Can someone help plz??

3. hartnn

did you try x= y^2?

4. anonymous

This is what you have written above: $$\lim{\sqrt{x}-2}$$ as $$x\rightarrow 4\sqrt{x^3}-8$$; unfortunately, this doesn't make sense. ($$x$$ can't approach something involving $$x$$). Could you re-check what you've written please?

5. MTALHAHASSAN2

yes I am sure this is what I have here

6. anonymous

Then it's a typo. Is it from a book?

7. hartnn

the question is |dw:1442760411721:dw|

8. anonymous

Ohhh... now THAT makes sense! Thanks!

9. anonymous

In what was posted above, somehow the division bar got lost.

10. hartnn

try x = y^2 when x->4 y->2

11. hartnn

then use the formula: $$\Large a^3 - b^3 = (a-b)(a^2+ab+b^2)$$

12. anonymous

It falls out nicely using l'Hopital's rule; too bad they specified a particular method!

13. MTALHAHASSAN2