Finding the instantaneous rate of change at t = 2hrs and t = 1hrs, the answer key for this past assignment gives 0 mph for t = 2hrs and 16mph for t = 1hrs, however for t = 1hrs I am only getting 12mph and for t = 2hrs I am getting 4 mph using the difference quotient f(x + h) − f(x)/h.
Using the same point f(x) and any different value for h should return the same instantaneous velocity, right?
#Finding the instantaneous rate of change from a graph at t = 2hrs and t = 1hrs
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No dude you want h to be super duper small like 0.00001
The smaller the h, the better the approximation for the “instantaneous rate of change”
Oh actually? I had no idea, I've just been using arbitrary points
Yeah
That makes way more sense though thinking about it. So here we would just use the smallest points we can see on the graph?
Wym
You were probably thinking of the secant line
Like for here at t(1hr) from the graph, without drawing a tangent line would I just use 1.125 as my next point?
Here we’re trying to find the tangent line
Yes! That was it, for average rate of change right?
Yeah
This makes way more sense now
You could do that but preferably something like 1 and 1.001
I got 16mph using 1.125
For sure
Just based on the key
Thank you so much Daniel!
Here I’ll link a desmos graph that shows why h needs to be small to get a tangent line. Play around with the h and p sliders
Thank you again!