The point of P(2,-1) lies on the curve y=1/(1-x). If Q is the point (x, 1/(1-x)), use your calculator to find the slope of the secant line PQ for the following values of x:
i) 1.5
ii) 1.9
iii) 1.99
iv) 1.999
v) 2.5
For parts i and ii of the question, I keep on getting the wrong answer... Could someone please help me out with this? Help with at least just "i" least would be appreciated.
I'll do the first one, the others are similar....(only the values have changed to protect the innocent...)
For, 1.5, we have the point on the curve
f(1.5) = 1 /(1 - 1.5) = 1 / (-.5) = -2
So we have two points (2, -1) and (1.5 , -2) and the slope of the secant line is [-2 - (-1)] / [1.5 - 2] = -1 / -.5 = 2
Here's the graph, here......note that the secant line drawn with these two enpoints would have a positive slope.
The point of this exercise is that is to show that the closer we get to x = 2, the more the secant line models the tangent line to the function at that point (i.e., the "derivative" at that point)
Hope this helps...
I'll do the first one, the others are similar....(only the values have changed to protect the innocent...)
For, 1.5, we have the point on the curve
f(1.5) = 1 /(1 - 1.5) = 1 / (-.5) = -2
So we have two points (2, -1) and (1.5 , -2) and the slope of the secant line is [-2 - (-1)] / [1.5 - 2] = -1 / -.5 = 2
Here's the graph, here......note that the secant line drawn with these two enpoints would have a positive slope.
The point of this exercise is that is to show that the closer we get to x = 2, the more the secant line models the tangent line to the function at that point (i.e., the "derivative" at that point)
Hope this helps...