Question

what is the maximum value of 3 - 7cos5x......plz give solution

Answer 1

In order to get the maximum value of 3 - 7cos5x, we have to minimise the term "7cos5x" as much as possible.

We all know that 7 is a constant so we cannot make any changes to it but to cos5x. Also, we know that the minimum and maximum range of cosx are -1 and +1; cos0=1 and cosπ=−1.

Therefore, cos5x must be equal to -1.

cos 5x = -1

or, Putting the value we get, 3 - 7*-1 = 3+7 = 10.

Thus, the maximum value of (3 - 7cos5x) is 10. [Ans]

Answer 2

In order to get the highest value of 3 - 7cos5x,

we have to minimize the expression "7cos5x" as much as possible.

Here 7 is a constant so we cannot make any changes to it but to cos5x.

Also, the minimum and maximum range of cosx are -1 and +1; cos0=1 and cosπ=−1.

As a result, cos5x must be equal to -1.

cos 5x = -1

Putting the value we get, 3 - 7*-1 = 3+7 = 10.

Therefore, the maximum value of (3 - 7cos5x) is 10