The point $ P(0.5, 0) $ lies on the curve $ y = \cos \pi x $.
(a) If $ Q $ is the point $ (x, \cos \pi x) $, use your calculator to find the slope of the secant line $ PQ $ (correct to six decimal places) for the following values of $ x $:
(i) $ 0 $ (ii) $ 0.4 $ (iii) $ 0.49 $
(iv) $ 0.499 $ (v) $ 1 $ (vi) $ 0.6 $
(vii) $ 0. 51 $ (viii) $ 0.501 $
(b) Using the results of part (a), guess the value of the slope of the tangent line to the curve at $ P(0.5, 0) $.
(c) Using the slope from part (b), find an equation of the tangent line to the curve at $ P(0.5, 0) $.
(d) Sketch the curve, two of the secant lines, and the tangent line.
Limits and Derivatives
The Tangent and Velocity Problems