See attachment :-)
\(\bf \Large lim_{x\rightarrow0} \sqrt{x} \ \ ?\)
lim h-->0 sqrt(x+h) -sqrt(x) / h
and then i'm stuck
\[\lim_{\Delta x \rightarrow 0}\frac{ \sqrt{x+\Delta x}-\sqrt{x} }{ \Delta x }=\lim_{\Delta x \rightarrow 0}\frac{ \sqrt{x+\Delta x}-\sqrt{x} }{ \Delta x } \times \frac{ \sqrt{x+\Delta x}+\sqrt{x} }{ \sqrt{x+\Delta x}+\sqrt{x} } \] \[= \lim_{\Delta x \rightarrow 0}\frac{ x+\Delta x-x }{ \Delta x \left( \sqrt{x+\Delta x}+\sqrt{x} \right)}= \lim_{\Delta x \rightarrow 0}\frac{ \Delta x }{ \Delta x \left( \sqrt{x+\Delta x}+\sqrt{x} \right)}=\lim_{\Delta x \rightarrow 0}\frac{ 1 }{ \left( \sqrt{x+\Delta x}+\sqrt{x} \right)}\]
\[=\lim_{\Delta x \rightarrow 0}\frac{ 1 }{ \left( \sqrt{x+\Delta x}+\sqrt{x} \right)}\] is the last part. Do you see what you get?
0?
1/2
c
idk why i thought the limit would be a number or undefined
\[\lim_{\Delta x \rightarrow 0}\frac{ 1 }{ \left( \sqrt{x+\Delta x}+\sqrt{x} \right)}=\frac{ 1 }{ \left( \sqrt{x+0}+\sqrt{x} \right)}= \text{ ?}\]
1/2sqrt(x)
experience helps with these things. when you do and see them a few times, i'll stick.
you got it.
it'll, not i'll
thank you i took calc more than ten years ago, practice is long gone for limits...for some reason those didn't stick in my head
no worries, glad to help
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