How do you verify the intermediate value theorem over the interval [0,5], and find the c that is guaranteed by the theorem such that f(c)=11 where f(x)=x^2+x-1?

1 Answer
Sep 4, 2017

The value of c=3

Explanation:

The Intermediate Value Theorem states that if f(x) is a continuous function on the interval [a,b] and N in (f(a), f(b)) , then there exists c in [a,b] such that f(c)=N

Here,

f(x)=x^2+x-1 is continuous on RR as it is a polynomial function.

The interval is I= [0,5]

f(0)=-1

f(5)=25+5-1=29

f(x) in [ -1, 29]

Then,

f(c)=11 , => 11 in [-1,29]

EE c in [0,5] such that f(c)=11

Therefore,

c^2+c-1=11, =>, c^2+c-12=0

(c+4)(c-3)=0

c=-4 and c=3

c=3 and c in [0,5]