Question

The given graph shows a function representing the speed of a car with time. Find the domain where the speed is constant.

• A. $1\le x\le 2$
• B. $2.8\le x\le 4$
• C. $0\le x\le 2.8$
• D. $2\le x\le 2.8$

Answer 1

The correct option is B $2.8\le x\le 4$

A function is said to be increasing if the correspoinding 'x' values are increasing.

Similarlly a function is said to be decreasing if the correspoinding 'x' values are decreasing.

Simillarly a function is said to be constant if the output or the value of y is always constant.

From the graph, we can observe:




Among them only portion D has constant speed 60 with the time.

$\therefore \text{So, domain of the function will be:}$
$2.8\le x\le 4$