Cos
θ
=
√
5
3
or it could be cos
θ
=
√
5
−
3
Explanation:
Since sin
θ
is negative, it can be in the third or fourth quadrant
Drawing your right-angled triangle, place your
θ
in one of three corners. Your longest side will be 3 and the side opposite the
θ
will be -2. Finally, using Pythagoras theorem, your last side should be
√
5
Now, if your triangle was in the third quadrant, you would have
cos
θ
=
√
5
−
3
since cosine is negative in the third quadrant
But if your triangle was in the fourth quadrant, you would have
cos
θ
=
√
5
3
since cosine is positive in the fourth quadrant
Let's say x is longest side, y is shortest side and z is the other side. So we have some equations such that

(by the first sentence)

(by the second sentence)

(by the third sentence)
By the second equation, we have

and if we use it in the first equation, then

. So

Since

, if we use it in the third equation the we have

then

Therefore
Answer:
The dependent variable for this experiment is the ability of students with similar intellectual abilities to recall the meaning of a symbol in a textbook one week after the start of the experiment which depends on the presence or absence of noise outside the classroom.
Step-by-step explanation:
In an experiment, the independent variable is the one whose value, form or outcome is not determined by any other variable in the experiment.
The dependent variable is the one whose value, form or outcome is determined by one or more other variable(s) in the experiment.
This experiment tests the abilities of students with similar intellectual abilities to recall the meaning of a symbol in a textbook one week after the start of the experiment.
This ability was made to depend on whether there was noise or no noise outside their classrooms.
Since, this variable to be measured is determined by another variable in the experiment, it is evident that this is the dependent variable for this experiment.
Hope this Helps!!!