From the given options, the only even function is the cosine function, so the correct option is A.
Which of the options is an even function?
First, an even function is a function with the property:
f(x) = f(-x)
So these functions are symmetrical across the y-axis.
Is ratter easy to remember that the sin function is actually odd, this means that:
sin(-x) = -sin(x).
Then the tangent function (and the cotangent function) are also odd, because:
tan(x) = sin(x)/cos(x).
In the other hand, for the cosine function we have:
cos(-x) = cos(x)
And as shown in the graph below, it is symmetrical across the y-axis.
Then we conclude that the correct option is A.
If you want to learn more about even functions:
https://brainly.com/question/2284364
#SPJ2
