Question

The graph of the hyperbolic cosine function for all real values is:

• A. Strictly increasing
• B. Strictly decreasing
• C. Strictly increasing in the interval $[0,\infty )$ and Strictly decreasing in the interval $(-\infty ,0]$
• D. Strictly increasing in the interval $(-\infty ,0]$ and Strictly decreasing in the interval $[0,\infty )$

Answer 1

The correct option is C Strictly increasing in the interval $[0,\infty )$ and Strictly decreasing in the interval $(-\infty ,0]$

In interval $[-\infty ,0]$ we have that $f\left(x_1\right)>f\left(x_2\right)$ when $x_1>x_2$

And in interval $[0,\infty ]$

So $cosine$ function is decreasing function in interval $[-\infty ,0]$

But increasing function in interval $[0,\infty ]$