MHB Limit x to o: $\lim_{h\to 0}=-\frac{1}{5}$

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The limit expression evaluates to -1/5, derived from the definition of the derivative of the function 1/x at x = 5. By manipulating the limit, the numerator and denominator are multiplied by 1/h, leading to the form -1/(5h + 25). As h approaches 0, this simplifies to -1/25. The discussion highlights the connection between limits and derivatives in calculus. The final conclusion confirms the limit's value as -1/25.
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$#46p60$
$$\lim_{{h}\to{0}}\frac{\frac{1}{5+h}-\frac{1}{5}}{h}=-\frac{1}{5}$$

Multiply numerator and denomator by $\frac{1}{h}$
$$\frac{-1}{5h+25}$$
$$h\to 0$$ thus $\frac{-1}{25}$

I hope anyway
 
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Correct! Alternatively, you might recognize this as the derivative of 1/x evaluated at x = 5, i.e.

$\displaystyle \lim_{{h}\to{0}}\frac{\frac{1}{5+h}-\frac{1}{5}}{h} = \frac{d}{dx} \left(\frac{1}{x}\right)\bigg|_{x=5} = -\frac{1}{x^2}\bigg|_{x=5} = -\frac{1}{25}.$
 
https://dl.orangedox.com/DllM3xBiyI8YRHbmhY
 
There are probably loads of proofs of this online, but I do not want to cheat. Here is my attempt: Convexity says that $$f(\lambda a + (1-\lambda)b) \leq \lambda f(a) + (1-\lambda) f(b)$$ $$f(b + \lambda(a-b)) \leq f(b) + \lambda (f(a) - f(b))$$ We know from the intermediate value theorem that there exists a ##c \in (b,a)## such that $$\frac{f(a) - f(b)}{a-b} = f'(c).$$ Hence $$f(b + \lambda(a-b)) \leq f(b) + \lambda (a - b) f'(c))$$ $$\frac{f(b + \lambda(a-b)) - f(b)}{\lambda(a-b)}...

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