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3 years ago

Find all solutions to the equation. cos^2x + 2 cos x + 1 = 0

1 answer:

6 0

$\bf cos^2(x)+2cos(x)+1=0\implies \stackrel{\textit{let's notice, this is simply }ax^2+bx+c=0}{[cos(x)]^2+2cos(x)+1=0} \\[2em] [cos(x)+1][cos(x)+1]=0 \\\\[-0.35em] ~\dotfill\\\\ cos(x)+1=0\implies cos(x)=-1\implies x=cos^{-1}(-1)\implies \stackrel{\textit{for the range }[0,2\pi ]}{x=\pi } \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill \stackrel{\textit{all solutions}}{x=\pi +2\pi n~~,~~ n \in \mathbb{Z}}~\hfill$

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Answer:

a.) 4

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c.) 8

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2 years ago

What is the fractional equivalent of the repeating decimal n=0.2727…?

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3 years ago

Ashley brought 7/8 gallon of lemonade to the party. her friends 2/3 drink of it. how many gallons of lemonade did they drink?

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3 years ago

Samir is an expert marksman. When he takes aim at a particular target on the shooting range, there is a 0.950.950, point, 95 pro

bearhunter [10]

The question is incomplete. Here is the complete question:

Samir is an expert marksman. When he takes aim at a particular target on the shooting range, there is a 0.95 probability that he will hit it. One day, Samir decides to attempt to hit 10 such targets in a row.

Assuming that Samir is equally likely to hit each of the 10 targets, what is the probability that he will miss at least one of them?

Answer:

40.13%

Step-by-step explanation:

Let 'A' be the event of not missing a target in 10 attempts.

Therefore, the complement of event 'A' is $\overline A=\textrm{Missing a target at least once}$

Now, Samir is equally likely to hit each of the 10 targets. Therefore, probability of hitting each target each time is same and equal to 0.95.

Now, $P(A)=0.95^{10}=0.5987$

We know that the sum of probability of an event and its complement is 1.

So, $P(A)+P(\overline A)=1\\\\P(\overline A)=1-P(A)\\\\P(\overline A)=1-0.5987\\\\P(\overline A)=0.4013=40.13\%$

Therefore, the probability of missing a target at least once in 10 attempts is 40.13%.

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3 years ago

Read 2 more answers

Mercury is a naturally occurring metal that can be harmful to humans. The current recommendation is for humans to take in no mor

kirill [66]

Answer:

A.) A person weights 80 kg can consume Haddock fish = 149 grams

B.) A person weights 80 kg can consume Swordfish fish = 8 grams

C.) A person weights 80 kg can consume Tuna fish = 23 grams

D.) A person weights 80 kg can consume Snapper fish = 50 grams

Step-by-step explanation:

Given - Mercury is a naturally occurring metal that can be harmful to humans. The current recommendation is for humans to take in no more than 0.1 microgram for every kilogram of their weight per day. Fish generally carry high levels of mercury, although certain fish have higher mercury content than others. Fish, however, are healthy sources of many other nutrients, so nutritionists recommend keeping them in the human diet. The figure below shows the average mercury content of several types of fish.

To find - If a person weighs 82 kg, how much of each fish can they safely consume? round to the nearest gram.

A.Haddock

B.Swordfish

C.Tuna

D.Snapper

Proof -

Firstly, determine how many micro grams of mercury a person can consume who weighs 82 kilograms.

⇒82 × 0.1 = 8.2 micro grams.

Now,

a.)

For Haddock fish-

It consumes 0.055 micro grams of mercury

So,

A person can consume fish = 8.2 ÷ 0.055

= 149.09 ≈ 149 grams

So,

A person weights 80 kg can consume Haddock fish = 149 grams

b.)

For Swordfish fish-

It consumes 0.995 micro grams of mercury

So,

A person can consume fish = 8.2 ÷ 0.995

= 8.24 ≈ 8 grams

So,

A person weights 80 kg can consume Swordfish fish = 8 grams

c.)

For Tuna fish-

It consumes 0.350 micro grams of mercury

So,

A person can consume fish = 8.2 ÷ 0.350

= 23.43 ≈ 23 grams

So,

A person weights 80 kg can consume Tuna fish = 23 grams

d.)

For Snapper fish-

It consumes 0.165 micro grams of mercury

So,

A person can consume fish = 8.2 ÷ 0.165

= 49.697 ≈ 50 grams

So,

A person weights 80 kg can consume Snapper fish = 50 grams

6 0

3 years ago