Important Theorems in Calculus  (continued)

 

The Intermediate Value Theorem:   i.e.  follows from continuity of a function

 

Suppose that  f  is continuous on the closed interval  [a,b] and  W  is any number

between  f(a) and f(b).  Then there is a number  c  in [a,b] for which  f(c)  =  W.

 

The graph below provides a geometric interpretation of the Intermediate Value Theorem.

 

 

 

This theorem is helpful in determining if roots exist in certain ranges for continuous

functions.

 

 

Example applying the Intermediate Value Theorem.   Problem Statement:

 

Use the Intermediate Value Theorem to verify that  f(x)  has a zero in the given

interval for     

                               f(x)  =  x3  -  4x  -  2    in    [-2, -1].

 

    Now    f(˗ 2)  =  ˗ 2,   f(-1)  =  +1,            Since f(˗ 2) < 0  and f(˗ 1)  > 0

 

     there exists a root (say  x = c) such that  f(c)  =  0.

 

 

 

Click here to continue with other important theorems.

 



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