Answer:
DIRECT CONTROL. Definition. HOLDING EXTRANEOUS FACTORS CONSTANT SO THAT THEIR EFFECTS ARE NOT CONFOUNDED WITH THOSE OF THE EXPERIMENTAL CONDITIONS. Term.
We have been given an equation
. We are asked to solve the equation for t.
First of all, we will divide both sides of equation by a.


Now we will take natural log on both sides.

Using natural log property
, we will get:

We know that
, so we will get:


Now we will divide both sides by c as:


Therefore, our solution would be
.
<h2>
Hello!</h2>
The answer is: 
<h2>
Why?</h2>
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:
: Incorrect, it does include 0.4 since the cosine range goes from -1 to 1 (-1 ≤ y ≤ 1)
Second:
: Incorrect, it also does include 0.4 since the cotangent range goes from is all the real numbers.
Third:
: Correct, the cosecant function is all the real numbers without the numbers included between -1 and 1 (y≤-1 or y≥1).
Fourth:
: 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!