Which of the following best corresponds to the x-value where the function f(x) = cosx is a minimum in the interval x=[25, 30]?
X
Ο Α. 25.1
O B. 26.7
OC. 28.3
OD. 29.8

Respuesta :

Answer:

C

Step-by-step explanation:

Cos x has a minimum of -1.

So Let find what x value in radians will equal -1

[tex] \cos(x) = - 1[/tex]

This occurs at x=pi

[tex] \cos {}^{ - 1} (1) = \pi[/tex]

Since cos is a periodic function, we add 2pi to it continously

[tex]\pi + 2\pi n[/tex]

convert pi to 3.14

[tex]3.14 + 2(3.14)n[/tex]

[tex]3.14 + 6.28n[/tex]

Let try when n is 4

[tex]3.14+(6.28)4[/tex]

[tex]3.14 + 25.12[/tex]

[tex]28.26[/tex]

[tex]28.3[/tex]