Proof check

Darya

Junior Member
Joined
Jan 17, 2020
Messages
154
I tried to recall the standard proof of [MATH]\lim_{x \to 0} \frac{e^x-1}{x}=1[/MATH] but then I got an idea and did this:
[MATH]\lim_{x \to 0} \frac{e^x-1}{x}=\lim_{x \to 0} \frac{((1+x)^{1/x})^x-1}{x}=\lim_{x \to 0} \frac{1+x-1}{x}=1[/MATH]I just wanted to check if it's valid to prove it this way. Thanks a lot!
 
Yes, it is OK but is missing some steps. You replaced ex with ((1+x)1/x)x but they are not equal. Do you see that?

Try to do it again.
 
Yes, it is OK but is missing some steps. You replaced ex with ((1+x)1/x)x but they are not equal. Do you see that?

Try to do it again.
Yes, e is equal to the limit of (1+x)^(1/x) when x approaches 0. The whole expression is in terms of limit so I skipped this step but agree that it should've been written in the proof.
 
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