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Punkte9466
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 #1
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(a)     Here's a graph:  https://www.desmos.com/calculator/fxto5gtfns

 

(b)     P  =  (2, 8)          Q  =  (x, x3)

 

Find the slope of the line  PQ  for the following values of  x .

 

When  x  =  1.5,   Q  =  (1.5, 1.53)  =  (1.5, 3.375)

 

We want to find the slope of the line passing through the points  (2, 8)  and  (1.5, 3.375)

 

slope  =  \(\frac{8-f(1.5)}{2-1.5}\,=\,\frac{8-3.375}{2-1.5}\,=\,\frac{4.625}{0.5}\,=\,9.25\)

 

This is the first value for the slope of the secant on the table.

 

x msec
   
1.5 9.25
   
1.9 \(\frac{8-f(1.9)}{2-1.9}\,=\,\frac{8-6.859}{2-1.9}\,=\,\frac{1.141}{0.1}\,=\,11.41\)
   
1.99         \(\frac{8-f(1.99)}{2-1.99}\,=\,\frac{8-7.880599}{2-1.99}\,=\,\frac{0.119401}{0.01}\,=\,11.9401\)
   
2 ?
   
2.01 \(\frac{8-f(2.01)}{2-2.01}\,=\,\frac{8-8.120601}{2-2.01}\,=\,\frac{-0.120601}{-0.01}\,=\,12.0601\)
   
2.1 \(\frac{8-f(2.1)}{2-2.1}\,=\,\frac{8-9.261}{2-2.1}\,=\,\)

 

Do you see how I am doing these? See if you can finish the table...

 

(c)

 

The slope of the tangent line when  x = 2  appears to be between  11.9401  and  12.0601

 

Let's just take the average of these two...                  (11.9401  +  12.0601) / 2  =  12.0001

 

So I'd guess that the slope of the tangent line at  (2, 8)  is  12    laugh

20.10.2017