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2 years ago

Prove the identity cos(A+B+C)=cosAcosBcosC-cosAsinBsinC-sinAcosBcosC-sinAsinBcosC

1 answer:

4 0

Hello !

cos (a+b) = cos a cos b - sin a sin b
sin (a+b) = sin a cos b + sin b cos a

cos (a+b+c) = cos (a+(b+c))
cos (a+b+c) = cos a cos (b+c) - sin a sin (b+c)
cos (a+b+c) = cos a (cos b cos c - sin b sin c) - sin a (sin b cos c + sin c cos b)
cos (a+b+c)=cos a cos b cos c - cos a sin b sin c - sin a sin b cos c - sin a cos b sin c

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Your drawer contains 10 red socks and 11 blue socks. It's too dark to see which are which, but you grab two anyway. What is the

beks73 [17]

For red there would be 1/22 and for blue there would be 1/22

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2 years ago

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Select all that apply. Which of the following are proportions? 25/10=5/2,3/4=8/10,2/8=3/12,3/4=15/20

8_murik_8 [283]

Answer:

$\frac{25}{10} = \frac{5}{2}$ is in proportion.

$\frac{3}{4} = \frac{8}{10}$ is not in proportion.

$\frac{2}{8} = \frac{3}{12}$ is in proportion.

$\frac{3}{4} = \frac{15}{20}$ is in proportion.

Step-by-step explanation:

The first example is $\frac{25}{10} = \frac{5}{2}$ and it is in proportion.

This is because, you will get the same simplest fraction ( $\frac{5}{2}$ ) from the fraction $\frac{25}{10}$ by dividing its numerator and denominator by 5.

The second example is $\frac{3}{4} = \frac{8}{10}$ and it is not in proportion.

This is because, you can not get the simplest fraction ( $\frac{3}{4}$ ) from the fraction $\frac{8}{10}$ after simplification.

The third example is $\frac{2}{8} = \frac{3}{12}$ and it is in proportion.

This is because, you will get the same simplest fraction ( $\frac{1}{4}$ ) from the fraction $\frac{2}{8}$ by dividing its numerator and denominator by 2 and from the fraction $\frac{3}{12}$ by dividing its numerator and denominator by 3.

The fourth example is $\frac{3}{4} = \frac{15}{20}$ and it is in proportion.

This is because, you will get the same simplest fraction ( $\frac{3}{4}$ ) from the fraction $\frac{15}{20}$ by dividing its numerator and denominator by 5. (Answer)

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2 years ago

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1/2x-5=10-3/4x please helpppppp

GarryVolchara [31]

Answer:

x=12

Step-by-step explanation:

1/2x - 5 = 10 - 3/4x ---> move like terms to the same side

1/2x + 3/4x = 10 + 5 ---> calculate

5/4x = 15 ---> multiply both sides by 4/5

x = 12

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1 year ago

What are the dimensions of the container holding a 1" x 1" x 1" cube

Allushta [10]

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What error did zacharias make?

qwelly [4]

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