Step-by-step explanation:
The number of subsets=2ⁿ where n=4 members
2ⁿ=2⁴=16
Number of proper subsets=2ⁿ-1
16-1=15
Answer:
I think it’s the first one, A
You got the right answers!
Horizontal and vertical
Congrats
165 -25 =140
140/7= 20.
20 hours
For this problem, I think there is no need for the details of 12 inches width and 4 inches length. This is because an equation is already given. It was clearly specified that A as a function of θ represents the area of the opening. Then, we are asked to find exactly that: the area of opening. Moreover, the value of θ was also given. Therefore, I am quite sure that the initial details given are for the purpose of red herring only.
So, all we have to do is substitute θ=45° to the function given.
A = 16 sin 45° ⋅ (cos 45° + 1)
The angle 45° is a special angle in trigonometry. So, it would be easy to remember trigonometric functions of this angle. Sine of 45° is equal to √2/2 while cosine of 45° is also √2/2.
A = 16(√2/2) ⋅ (√2/2 + 1)
A = 8+8√2
A = 19.31 square inches
