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the function cosh(cosx) decreases in the interval? give procedure to solve these type of problems

the function cosh(cosx) decreases in the interval?


give procedure to solve these type of problems


 

Grade:11

1 Answers

SAGAR SINGH - IIT DELHI
878 Points
13 years ago

Dear student,

Just expand it...

Theorem on Increasing and Decreasing of Functions:

Let f be continuous on [a, b] and differentiable on the open interval (a, b). Then

(a) f is increasing on [a, b] if f '(x) > 0 for each x (a, b)

(b) f is decreasing on [a, b] if f '(x) < 0 for each x (a, b)

This theorem can be proved by using Mean Value Theorem. We shall prove the theorem after learning Mean Value Theorem.

This theorem is applied in various problems to check whether a function is increasing or decreasing.

Increasing and Decreasing Function Working Rule

(1) Let the given function be f (x) on the real number line R.

(2) Differentiate the function f(x) with respect to x and equate it to zero i.e., put f '(x) = 0. Solve for x. These values of x which satisfy f '(x) = 0 are called Critical values of the function

(3) Arrange these Critical values in ascending order and partition the domain of f (x) into various intervals, using the Critical values.

(4) Check the sign of f '(x) in each open intervals.

(5) If f '(x) > 0 in a particular interval, then the function is increasing in that particular interval.

If f '(x) < 0 in a particular interval, then the function is decreasing in that particular interval.

 

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Askiitians Expert

Sagar Singh

B.Tech, IIT Delhi

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