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mojhsa [17]
2 years ago
9

If cosa=1/2(a+1/a), verify that. cos2a=1/2(a²+1/a²)​

Mathematics
1 answer:
Alborosie2 years ago
3 0

Answer:

see explanation

Step-by-step explanation:

using the identity

cos2a = 2cos²a - 1 , then

cos2a

= 2[ \frac{1}{2}(a  + \frac{1}{a}) ]² - 1

= 2 [ \frac{1}{4} (a² + \frac{1}{a^2} + 2) ] - 1

= \frac{1}{2} (a² + \frac{1}{a^2} ) + 1 - 1

= \frac{1}{2} (a² + \frac{1}{a^2} ) ← thus verified

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Answer: I can’t draw lol

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Kray sells personalized photo frames. She charges $12 for the frame plus $0.25 for each letter the customer wants to engraved on
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The wheel on a bicycle has a diameter of 20 centimeters. What is the length of the rubber required to make a tire that will cove
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Step-by-step explanation:

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3 years ago
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According to a survey, 18% of the car owners said that they get the maintenance service done on their cars according to the sche
Annette [7]

Answer:

a) For this case we define the random variable X="number of car owners in a random sample of 12 who get the maintenance service done on their cars according to the schedule recommended by the auto company". And for this case the distribution for X is:

X \sim Binom (n =12, p=0.18)

And the possible values for the random variable are X=0,1,2,3,4,5,6,7,8,9,10,11,12

b) Using the probability mass function we got:

P(X=3)=(12C3)(0.18)^3 (1-0.18)^{12-3}=0.21506

Step-by-step explanation:

Previous concepts

A Bernoulli trial is "a random experiment with exactly two possible outcomes, "success" and "failure", in which the probability of success is the same every time the experiment is conducted". And this experiment is a particular case of the binomial experiment.

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

The probability mass function for the Binomial distribution is given as:  

P(X)=(nCx)(p)^x (1-p)^{n-x}  

Where (nCx) means combinatory and it's given by this formula:  

nCx=\frac{n!}{(n-x)! x!}  

Solution to the problem

Part a

For this case we define the random variable X="number of car owners in a random sample of 12 who get the maintenance service done on their cars according to the schedule recommended by the auto company". And for this case the distribution for X is:

X \sim Binom (n =12, p=0.18)

And the possible values for the random variable are X=0,1,2,3,4,5,6,7,8,9,10,11,12

Part b

Find to 3 decimal places the probability that exactly 3 car owners in a random sample of 12 get the maintenance service done on their cars according to the schedule recommended by the auto company.

Using the probability mass function we got:

P(X=3)=(12C3)(0.18)^3 (1-0.18)^{12-3}=0.21506

6 0
3 years ago
The hypotenuse of a right triangle is twice the length of one of its legs. Th length of the other leg is three feet. Find the le
IgorLugansk [536]
Let
x----> the length side of the hypotenuse
y----> the length side of the <span>unknown leg

we know that
x=2*y----> equation 1
applying the Pythagoras Theorem
x</span>²=y²+3²-----> equation 2

substitute equation 1 in equation 2
[2*y]²=y²+3²----> 4*y²-y²=9-----> 3*y²=9----> y²=3
y=√3 ft
x=2*y----> x=2*√3 ft

the answer is
<span>the lengths of the three sides are
</span>hypotenuse=2√3 ft
one leg=√3 ft
other leg=3 ft

7 0
3 years ago
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