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earnstyle [38]
3 years ago
12

Find all solutions to the equation. cos2x + 2 cos x + 1 = 0

Mathematics
1 answer:
yanalaym [24]3 years ago
5 0
For cos(2x) * (2cos(x) + 1) = 0, use the double angle identity for cos(2x), which is cos^2 x - sin^2 x = cos^2 x - (1-cos^2) = 2cos^2 x - 1.
So we have (2cos^2 x - 1)(2cos x + 1) = 0. So 2cos^2 x -1 = 0 or x = 0 and 2pi.
For 2sec^2 x + tan^2 x - 3 = 0, use the identity sec^2 x = tan^2 x + 1, so we have
2(tan^2 x + 1) + tan^2 x - 3 = 0 or
<span>2tan^2 x + tan^2 x - 1 = 0 or
</span>3 tan^2 x = 1.

So x = pi/2, pi/2 + pi = 3pi/2.

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Algebra help (picture is included)
SVETLANKA909090 [29]
\boxed {\boxed {\text {Volume = base area x height}}}

Base Area = 2 x 2 = 4 cm²

Volume = 4 x 3.5 = 14 cm³

Answer: 14 cm
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3 0
4 years ago
A cd has 5% chance of being a smash hit an profiting $5.2 million a 50% chance of being a modest success and profiting $0.9 mill
Aleksandr [31]

Answer:

710,000

Step-by-step explanation:

P(S) = Probability of Smash = 0.05 (5%)

P(M) = Probability of Modest = 0.5 (50%)

P(F) = Probability of Flop = 0.45 (45%)

Use the discrete random variable model,

E(X) = (0.05 * 5.2) + (0.5 * 0.9) + (0.45 * 0)

= 0.26 + 0.45 + 0 = 710,000

3 0
3 years ago
NEED THE ANSWER ASAP <br> MARKING BRAINLIEST
Phantasy [73]

Answer:

A=74.24 f^2

Step-by-step explanation:

Triangle:

1/2 x 6x 8

=24

Half a circle

3.14x 4^2 ÷ 2

=25.12

Then plus it together

24+25.12

=49.12 ft

3 0
3 years ago
What is the percent change from 54 to 42
storchak [24]
What is the percent change from 54 to 42? 12 %
5 0
4 years ago
Read 2 more answers
The are 30 students on the cheerleading squad. The membership went up by 10%. How many more students joined the squad? Please ex
Andrej [43]

Answer:

3 students joined the squad

Step-by-step explanation:

10% is 10/100 = 1/10

10% of 30 = (1/10)×30 = 30/10 = 3

When we say, "the membership went up by 10%", we mean that the increase in membership is equal to 10% of the original membership. That is, the increase is 10% of 30, or 3 members.

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The words "per cent" literally mean "per hundred" or "divided by one hundred." The symbol "%" means "/100" and can be considered to be a shorthand way to write "/100". (Likewise, the symbol "‰" means "/1000".)

So, 10% = 10/100, ten hundredths. As a decimal, you know ten hundredths is 0.10. These various representations all have the same value.

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In math problems, the word "of" often means "times." That is, it is an indication of multiplication.

"10% of 30" means "0.10×30", for example.

___

When dealing with percentage changes, the change is always in relation to some original amount. It is important to identify what original amount is being talked about when talking about percentage changes.

Here, the original amount is the number of students on the squad before any changes took place. That number is 30 students. Then, the change is the percentage of (times) the original amount, so 10% of 30 students.

4 0
4 years ago
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