Answer:
(a)
(b)
(c)
Step-by-step explanation:
Number of juniors who attended prom,n(J)=28
Number of seniors who attended prom,n(S)=97
- Total of those who attended prom=125
Number of juniors who did not attend prom,n(J')=56
Number of seniors who did not attend prom,n(S')=19
- Total of those who attended prom=75
- Total Number of students=200
(a) P (a junior who did not attend prom)

(b)


(c)P (junior | attended prom)


Consider the picture attached.
From right triangle trigonometry:
tan(α)=(opposite side)/(adjacent side)=15/67=0.2239
using a scientific calculator we find that arctan(0.2239)=12.62°
thus α=12.62°, is the angle that the vector makes with the positive x-axis.
The angle made with the + y-axis is 12.62°+90°=102.62°.
The length of the vector v can be determined using the Pythagorean theorem:

Thus, to make v a unit vector, without changing its direction, we need to divide v by |v|=68.8.
This means that the x and y components will also be divided by 68.8, by proportionality.
So, the unit vector in the direction of v is:
<span>(67/68.8)i + (-15/68.8)j=0.97 i + (- 0.22)j
</span>
Answer: 12.62°; 102.62°; 0.97 i + (- 0.22)j
Confused what the question is. Are you looking for the product or the zeroes?
If you are looking for the product, then:
Use foil to get: sec²(1) - sec²(-csc²) -1(1) -1(-csc²)
= sec² + sec²csc² - 1 + csc²
= sec²csc² + sec² + csc² - 1
= sec²csc² + 1 - 1 (NOTE: sec² + csc² = 1 is an identity)
= sec²csc²
Answer: sec²csc²
***************************************************
If you are looking for the zeroes, then:
Using the zero product property, set each factor equal to zero and solve.
<u>First factor:</u>
sec²Θ - 1 = 0
sec²Θ = 1
secΘ = 1, -1
remember that secΘ is 
= 1
= -1
cross multiply to get:
cosΘ = 1 cosΘ = -1
use the unit circle (or a calculator) to find that Θ = 0 and π
<u>Second factor:</u>
1 - csc²Θ = 0
1 = csc²Θ
1, -1 = cscΘ
remember that cscΘ is 
= 1
= -1
cross multiply to get:
sinΘ = 1 sinΘ = -1
use the unit circle (or a calculator) to find that Θ =
and
Answer: 0, π,
,