Answer:
D
Step-by-step explanation:
our basic Pythagorean identity is cos²(x) + sin²(x) = 1
we can derive the 2 other using the listed above.
1. (cos²(x) + sin²(x))/cos²(x) = 1/cos²(x)
1 + tan²(x) = sec²(x)
2.(cos²(x) + sin²(x))/sin²(x) = 1/sin²(x)
cot²(x) + 1 = csc²(x)
A. sin^2 theta -1= cos^2 theta
this is false
cos²(x) + sin²(x) = 1
isolating cos²(x)
cos²(x) = 1-sin²(x), not equal to sin²(x)-1
B. Sec^2 theta-tan^2 theta= -1
1 + tan²(x) = sec²(x)
sec²(x)-tan(x) = 1, not -1
false
C. -cos^2 theta-1= sin^2
cos²(x) + sin²(x) = 1
sin²(x) = 1-cos²(x), our 1 is positive not negative, so false
D. Cot^2 theta - csc^2 theta=-1
cot²(x) + 1 = csc²(x)
isolating 1
1 = csc²(x) - cot²(x)
multiplying both sides by -1
-1 = cot²(x) - csc²(x)
TRUE
Answer:



Step-by-step explanation:
Given
--- 8 friends
--- proportion that one-time fling
This question is an illustration of binomial probability, and it is represented as:

Solving (a): P(x = 0) --- None has done one time fling




Solving (b): 
To do this, we make use of compliment rule:

Rewrite as:



Solving (c):
--- Not more than 2 has one time fling
This is calculated as:

We have:







So:



Answer:
You are selecting marbles with replacement. The marble selections (trials) are independent and the marble selection follows the binomial distribution.
The probability of selecting a red marble the first time is 1313.
(This is because 4 out of 12 marbles are red and412412 reduces to 1313.
The probability of selecting a red marble the second time is 1313.
The marble selections are independent and you can multiply the two probabilities to get the following:
probability of getting 2 reds = (13)2(13)2
=19=19.
So the probability of getting two reds is 1919.