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If working in radians, the cosine of one-quarter of pi is equal to the square root of 0.5. Squaring this gives 0.5, or exactly one-half.

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What is the exact value of the expression cos 7pi over 12 cos pi over 6 -sin 7pi over 12 sin pi over 6?

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What is the exact value using a sum or difference formula of the expression cos 11pi over 12?

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What is the value of cos pie4?

cos pi over four equals the square root of 2 over 2 This value can be found by looking at a unit circle. Cos indicates it is the x value of the point pi/4 which is (square root 2 over 2, square root 2 over 2)


What is the diameter of the circle that has a circumference equal to its area?

The diameter is 4 and its radius is 2 because 2+2 = 4 and 2 squared = 4 Circumference of the circle: pi*4 is the same as pi*2 squared Area of the circle: pi*2 squared


What are the distinct fourth root of -1?

The four roots are cos(theta)+i*sin(theta) where theta = pi/4, 3*pi/4, 5*pi/4 and 7*pi/4.


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area = pi x diameter squared/4 = 400 pi diameter squared = 4 x 400 x pi/pi = 1600 diameter = sqrt 1600 = 40


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That is correct because the surface area of a sphere is: 4*pi*radius squared


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What is the side length of an 8 inch diameter octagon?

The side length is 2/[cos(pi/4)*cos(pi/8)] = 3.06 inches, approx.


What is the area of a 4' circle?

It is: pi*radius squared