Question

Which trigonometric function has a range that does not include 0.4?

Answer 1

Hello!

The answer is: $y=cscx$

Why?

Domain and range of trigonometric functions are already calculated, so let's discard one by one in order to find the correct answer.

The range is where the function can exist in the vertical axis when we assign values to the variable.

First:

$y=cosx$: Incorrect, it does include 0.4 since the cosine range goes from -1 to 1 (-1 ≤ y ≤ 1)

Second:

$y=cotx$: Incorrect, it also does include 0.4 since the cotangent range goes from is all the real numbers.

Third:

$y=cscx$: Correct, the cosecant function is all the real numbers without the numbers included between -1 and 1 (y≤-1 or y≥1).

Fourth:

$y=sinx$ : Incorrect, the sine function range is equal to the cosine function range (-1 ≤ y ≤ 1).

I attached a pic of the csc function graphic where you can verify the answer!

Have a nice day!