How do you verify the intermediate value theorem over the interval [0,3], and find the c that is guaranteed by the theorem such that f(c)=4 where f(x)=x^3-x^2+x-2?

2 Answers
Aug 14, 2017

f is a polynomial so f is continuous on the interval [0,3].

f(0) = -2 and f(3) = 19

4 is between f(0) and f(3) so IVT tells us that there is a c in (0,3) with f(c) = 4

Finding the c requires solving

x^3-x^2+x-2 = 4. Which is equivalent to

x^3-x^2+x-6 = 0

Possible rational zeros are +-1, +-2, +-3, and +-6.

Testing shows that 2 is a solution.

So c = 2

Aug 14, 2017

The value of c in (0, 3) and is c=2

Explanation:

The intermediate value theorem states that if f(x) is a continuous function on the interval [a,b], then there is a number p between f(a) and f(b), (f(a)!=f(b)) such that there is a number c in (a,b) such that p=f(c)

Here, f(x)=x^3-x^2+x-2, which is a polynomial function continuous on the Interval [0,3]

f(0)=0-0+0-2=-2

f(3)=3^3-3^2+3-2=27-9+3-2=19

f(c) in (f(0, f(3)))

f(c)=4 such that c in (0,3)

Therefore,

f(c)=c^3-c^2+c-2=4

=>, c^3-c^2+c-6=0

f(2)=2^3-2^2+2-2=8-4+2-2=4