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Use the intermediate value theorem to show that there is a root of the equation x5 - 2x4 - x - 3 = 0 in the interval (2,3).
Solution:
Given, the equation is x5 - 2x4 - x - 3 = 0
We have to find the root of the equation in the interval (2, 3) using the intermediate value theorem.
Let f(x) = x5 - 2x4 - x - 3
f(2) = (2)5 - 2(2)4 - 2 - 3
f(2) = 32 - 32 - 5
f(2) = -5
f(3) = (3)5 - 2(3)4 - 3 - 3
f(3) = 243 - 162 - 6
f(3) = 75
Intermediate value theorem states that if a continuous function f(x) on the interval [a,b] has values of opposite sign inside an interval, then there must be some value x = c on the interval (a,b) for which f(c) = 0.
f(x) is continuous on the interval [2, 3] because it is a polynomial function, and is continuous at each point in the interval.
Here, f(2) is negative and f(3) is positive.
Therefore, f(x) is continuous on the closed interval [2, 3], there must be some value x = c on the interval [2, 3] for which f(c) = 0.
Use the intermediate value theorem to show that there is a root of the equation x5 - 2x4 - x - 3 = 0 in the interval (2,3).
Summary:
Using the intermediate value theorem, the equation x5 - 2x4 - x - 3 = 0 is continuous on the closed interval [2, 3], there is a root of the equation in the interval (2,3).
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