Evaluating a Limit: Examining lim h->0 ((8+h)^⅓ -2)/h

  • Thread starter Thread starter Aviegaille
  • Start date Start date
  • Tags Tags
    Limit
Aviegaille
Messages
7
Reaction score
0

Homework Statement


Evaluate lim h->0 ((8+h)^⅓ -2)/h.

Homework Equations


Hint: Let 8+h=x^3

The Attempt at a Solution


I've uploaded a picture of my calculation. But I am not sure if that is the final answer or is there a following step to get the answer.
 

Attachments

  • 10715861_758452074233478_1217445669_n.jpg
    10715861_758452074233478_1217445669_n.jpg
    45.8 KB · Views: 506
Physics news on Phys.org
Why do you think that as h->0 with x^3=8+h that x->(-3)? And why do you think that (x^3)^(1/3)=x^3?
 
Aviegaille said:

Homework Statement


Evaluate lim h->0 ((8+h)^⅓ -2)/h.

Homework Equations


Hint: Let 8+h=x^3

The Attempt at a Solution


I've uploaded a picture of my calculation. But I am not sure if that is the final answer or is there a following step to get the answer.

Please do not post thumbnails; they cannot be viewed on some media! Just type out things directly.
 
I don't know exactly which of many possible methods you are expected to use here, but did you notice that this limit is precisely that defining the derivative of f(x) at x= 8, with f(x)= x^{2/3}?
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...

Similar threads

Back
Top