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ipn [44]
4 years ago
8

Show how you could set up and find the exact value of cos(5π/4) in two different ways.

Mathematics
1 answer:
Schach [20]4 years ago
6 0

note that 5π /4 is in the third quadrant where the cos is negative

the related acute angle to 5π /4 is π/4, thus

cos( 5π /4 ) = - cos (π/4 ) = - √2/2

We can also evaluate using the addition formula for cosine

• cos (x + y ) = cosxcosy - sinxsiny

note that 5π /4 = (π + π/4 )

cos(5π /4 ) = cos (π + π/4 )

= cos(π)cos(π/4) - sin(π)sin(π/4)

= - 1 √2/2 - 0 = - √2/2


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Help???????????!!!!!!!!!!!
Butoxors [25]
Salutations!

12 \frac{2}{3}

- 9 \frac{3}{4}

= \frac{38}{3} 

Then,

- 9 \frac{3}{4}

- \frac{39}{4}

Next, our final answer:

= \frac{35}{12}

= 2 \frac{11}{12} 

Our decimal would be 2.916667

Hopefully This Helps!!!

 
3 0
3 years ago
Suppose a circle has a radius of 13 inches. How far would a 24 inch chord be from the center of the circle? (Hint: Draw a diagra
lys-0071 [83]

Answer:

Step-by-step explanation:

Directions

  • Draw a circle
  • Dear a chord with a length of 24 inside the circle. You just have to label it as 24
  • Draw a radius that is perpendicular and a bisector through the chord
  • Draw a radius that is from the center of the circle to one end of the chord.
  • Label where the perpendicular radius to the chord intersect. Call it E.
  • You should get something that looks like  the diagram below. The only thing you have to do is put in the point E which is the midpoint of CB.

Givens

AC = 13 inches                   Given

CB = 24 inches                  Given

CE = 12 inches                    Construction and property of a midpoint.

So what we have now is a right triangle (ACE) with the right angle at E.

What we seek is AE

Formula

AC^2 = CE^2 + AE^2

13^2 = 12^2 + AE^2

169 = 144 + AE^2                     Subtract 144 from both sides.

169 - 144 = 144-144 + AE^2     Combine

25 = AE^2                                Take the square root of both sides

√25 = √AE^2

5 = AE

Answer

The 24 inch chord is 5 inches from the center of the circle.

4 0
2 years ago
Read 2 more answers
These are some maths gcse questions pls answer
astra-53 [7]

Answer:

The difference between 5 and a certain number is divided by 3. find the number if is equal to 7.

4 0
2 years ago
Please help me on this problem​
lara [203]

Answer:

The first one?

Step-by-step explanation:

sorry if im wrong

7 0
3 years ago
Read 2 more answers
Please help :D i give brainliest
Over [174]

Answer:

  • 10 cm, 20 cm, 20 cm

Step-by-step explanation:

Let the base is x, then the legs are 2x each.

<u>The perimeter is:</u>

  • x + 2x*2 = 50
  • 5x = 50
  • x = 10

The base is 10 cm and legs are 20 cm each.

8 0
3 years ago
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