First principles of differentation - Help Please (1 Viewer)

[Smile12345]

Can someone please help me with this question...

For the function f(x)= x^-1 (x to the power of -1)
a) Evaluate f(x)- f(5) / x - 5... When x = 4.99

Thanks heaps....

 

[braintic]

As you have not mentioned limits, it is a simple substitution.

 

[Smile12345]

As you have not mentioned limits, it is a simple substitution.

Awe yeah... Thanks heaps... Sometimes I think too complex! Do you ever have that trouble?

Braintic... The next part was to evaluate when x = 5.01... I've got that answer... Now I have to use these results to find the derivative of the function at the point where x = 5... How do I do this?

 

[Sy123]

Awe yeah... Thanks heaps... Sometimes I think too complex! Do you ever have that trouble?

Braintic... The next part was to evaluate when x = 5.01... I've got that answer... Now I have to use these results to find the derivative of the function at the point where x = 5... How do I do this?

First principles:









The use of x=4.99 and x=5.01 is rather silly, but essentially when you substituted those values into the formula, you are finding the gradient of the chord from x=5 to x=4.9 and so on. And this show give an estimate as to the gradient of the tangent (the derivative)

 

[Smile12345]

First principles:









The use of x=4.99 and x=5.01 is rather silly, but essentially when you substituted those values into the formula, you are finding the gradient of the chord from x=5 to x=4.9 and so on. And this show give an estimate as to the gradient of the tangent (the derivative)

Thanks Sy...Yes, sometimes textbook questions can be quite silly, I agree. Thanks again for your explanation...