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Andreas93 [3]
3 years ago
6

Angles A and B are located in the first quadrant such that sinA= 7/25 and cosB = 5/13. Determine the exact value for cos (A-B).

Mathematics
1 answer:
fomenos3 years ago
8 0

Answer:

  204/325

Step-by-step explanation:

You can work this a couple of ways. We expect you are probably expected to use trig identities.

  cos(A) = √(1 -sin²(A)) = 24/25

  sin(B) = √(1 -cos²(B)) = 12/13

cos(A -B) = cos(A)cos(B) +sin(A)sin(B) = (24/25)(5/13) +(7/25)(12/13)

  = (24·5 +7·12)/325

cos(A -B) = 204/325

__

The other way to work this is using inverse trig functions. It is necessary to carry the full calculator precision if you want an exact answer.

  cos(A -B) = cos(arcsin(7/25) -arccos(5/13)) = cos(16.2602° -67.3801°)

  = cos(-51.1199°) ≈ 0.62769230 . . . . (last 6 digits repeating)

The denominators of 25 and 13 suggest that the desired fraction will have a denominator of 25·13 = 325, so we can multiply this value by 325 to see what we get.

  325·cos(A-B) = 204

so, the exact value is ...

  cos(A -B) = 204/325

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What is the mean median and mode for 50, 55,42,38,163,55,61​
Likurg_2 [28]

Answer:

Mean: 67.7 (rounded to the nearest tenth)

Median: 52.2

Mode: 55

Step-by-step explanation:

To find the the mean is to take all the numbers, all them together and divide by how many numbers there is. 50+55+42+38+163+55+61= 564 then divided by 6 is 67.7

to find the median is to put all the numbers in order, (I prefer to go increasing order) and then find the middle number. If there is no  middle number you take the two numbers around it and subtract them from one n another.

Mode is to find the most common number. Whichever number repeats itself

Hope I helped!

3 0
3 years ago
8th grade math . Pythagorran practice <br>​
Serhud [2]

The answers according to rows are:

  • ROW 1 : diameter of base = 10,  base area = 25π, volume of cylinder = 175π    volume of cone = \frac{175}{3}π
  • ROW 2 : base radius = 3, base area = 9π, height = 40/3, volume of cylinder = 120π
  • ROW 3 : base radius = 6, base diameter = 12, height = 4, volume of cylinder = 144π

<h3>What is mensuration?</h3>

Mensuration is an aspect of geometry that deals with measurement of volumes and area.

Analysis:

Row 1

Diameter of base = 2 x radius = 2 x 5 = 10

Base area = πr^{2} = π(5)^{2} = 25\pi

Volume of cylinder = base area x height = 25π x 7 = 175π

Volume of cone  = 1/3 x volume of cylinder = 175π/3

Row 2

Base radius = base diameter/2 = 6/2 = 3

Base area = πr^{2} = π(3)^{2} = 9π

Volume of cone = 1/3 x base area x height

base area x height  = 3 x volume of cone

base area x height = 3 x 40π

Height = 120π/9π = 40/3

Cylinder volume = 3 x cone volume = 3 x 40π = 120π

Row 3

Base area = πr^{2}

36π =  πr^{2}

r2 = \sqrt{36}

r = 6

Base diameter = 2 x 6 = 12

Volume of cone  = 1/3 x base area x height

48π = 1/3 x 36π x height

Height = 4

Cylinder volume = 3 x 48 = 144π

In conclusion,

ROW 1 : diameter of base = 10,  base area = 25π, volume of cylinder = 175π

volume of cone = \frac{175}{3}π

ROW 2 : base radius = 3, base area = 9π, height = 40/3, volume of cylinder = 120π

ROW 3 : base radius = 6, base diameter = 12, height = 4, volume of cylinder = 144π

Learn more about mensuration: brainly.com/question/18541562

#SPJ1

4 0
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dlinn [17]

Answer:

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Step-by-step explanation:

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11/14 simplified:


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3 years ago
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sergey [27]
19) 48 alligators; 7/8 of the alligators were asleep. How many were not asleep?

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Tia got more hits.
3 0
3 years ago
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