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Sati [7]
3 years ago
12

Prove that:cos20°cos40°cos80°=1/8​

Mathematics
2 answers:
Naya [18.7K]3 years ago
7 0

Answer:

see explanation

Step-by-step explanation:

Using the double angle identity for sine

sin2x = 2sinxcosx

Consider left side

cos20°cos40°cos80°

= \frac{1}{2sin20} (2sin20°cos20°)cos40°cos80°

= \frac{1}{4sin20} (2sin40°cos40°)cos80°

= \frac{1}{4sin20} (sin80°cos80° )

= \frac{1}{8sin20} (2sin80°cos80° )

= \frac{1}{8sin20} . sin160°

= \frac{1}{8sin20} . sin(180 - 20)°

= \frac{1}{8sin20} . sin20°

= \frac{1}{8} = right side , thus proven

viva [34]3 years ago
7 0

Step-by-step explanation:

hope its helps you have a great day keep smiling be happy stay safe ☺

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Convert 6200 seconds into weeks. Round your answer to the nearest hundredth
musickatia [10]

Answer:

0.01 weeks

Step-by-step explanation:

1 min=60sec

1hr=3600sec

1 day = 86400sec

1 week= 604800sec

Therefore answer is 6200/604800= 0.01(approximated)

6 0
2 years ago
Which expression is quick to
Len [333]

Answer:

4⁰ is the answer

Step-by-step explanation:

because first you change the division sign to a multiplication sign because they are the same and then multiply the terms with same base by adding their exponent which looks like this 4⁵-⁷+²

then calculate the sum or difference and you get 4⁰ [hopefully this makes sense]

3 0
3 years ago
If BC = 61 and AB = 82, what is the length of AC?
Nitella [24]

Answer:

54.8

Step-by-step explanation:

Pythagorean theorem is a^2+b^2=c^2.

Plug the given values in to get 61^2+b^2=82^2

61^2 is 3,721 and 82^2 is 6,724.

6,724-3,721 is 3,003.

The square root of 3,003, rounded to a reasonable value, is 54.8.

The length of AC is 54.8.

4 0
3 years ago
How many significant digits is in 70.00?
julia-pushkina [17]
Going by what I was taught in chemistry, there would only be 1.
3 0
3 years ago
PLEASE HELP!
Paul [167]

Step-by-step explanation:

coefficient=w

variable=w

result=

32=w-4

w=4+32

w=36

constant=32,4

8 0
3 years ago
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