Interactive · 5 questions
Let's try to estimate the derivative of at , and let's suppose we can't use the Product Rule.
What is the value of at ?
Which of the following denotes the derivative of at ?
Since we cannot determine the limit explicitly, what information would be helpful for estimating the limit?
Great! Let's take . What estimate for the derivative of at does this give us?
Great! Remember that we use to estimate the derivative of at . For we get which is about .
The actual value of the derivative is . How could we get a better estimate of the derivative?
Indeed! If we take , our approximation yields which is about .
If we take , our approximation yields .
This is the basic idea behind approximating derivatives with function values!