Intermediate value theorem

In summary, it is being discussed how to prove that the equation (1-x)Cosx=Sinx has at least one solution in the interval (0,1) and is also continuous. It is mentioned that all three terms in the equation are continuous and that it is straightforward to prove the continuity of the whole expression using the definition of continuity. There is also a question about whether the continuity of each term needs to be proven first.
  • #1
ken1101
3
0
prove that the equation (1-x)Cosx=Sinx has at least one solution in (0,1)

I am having some problem in proving that the equation is continous.

Please help. Thank you
 
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  • #2
1-x , cosx, sinx are all continuous, and you are not doing any dividing, so continuity is obvious.
 
  • #3
I realize it is continous. I just need prove that it is continuous using the definition of continuous

for every ε > 0 there exists a δ > 0 such that for all x ∈ I,: |x-c|<δ⇒|f(x)-f(c)|<ε
 
  • #4
Can you assume each of the three terms are continuous or do need to first prove that? Once that is done, it is straightforward for whole expression since absolute value of each term is ≤ 1.
 

What is the Intermediate Value Theorem?

The Intermediate Value Theorem is a theorem in calculus that states that if a continuous function has a different sign at two points in its domain, then it must have at least one root (or zero) between those two points.

What is the significance of the Intermediate Value Theorem?

The Intermediate Value Theorem is important because it guarantees the existence of roots for certain continuous functions. This allows us to use the theorem to prove the existence of solutions to equations that cannot be solved algebraically.

How is the Intermediate Value Theorem used in real-life applications?

The Intermediate Value Theorem is used in a variety of real-life applications, such as in economics to prove the existence of equilibrium points, in physics to prove the existence of solutions to certain equations, and in computer science to design algorithms for finding roots of functions.

What are the conditions for the Intermediate Value Theorem to hold?

The Intermediate Value Theorem requires that the function is continuous on a closed interval and that the function has a different sign at the endpoints of the interval. If these conditions are met, then the theorem guarantees the existence of at least one root on that interval.

Can the Intermediate Value Theorem be applied to functions that are not continuous?

No, the Intermediate Value Theorem only applies to continuous functions. If a function is not continuous, then it is not guaranteed to have a root between two points where it has a different sign. However, there are other theorems and methods that can be used to find roots of non-continuous functions.

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