Can you help with this
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Answer:
Step-by-step explanation:
the volume of a cylinder is given by:
where r is the radius and h is the height.
and the surface area:
the first term is the area of the circles and the second term is the area of the body.
since "The number of volume of a cylinder is half of its number of the total surface area." we will have that:
substitutig the equivalent expressions on each side:
and we simplify and solve for the height (since is the value we don't know of the cylinder):
we substitute the value of the radius , and we get:
thus the volume is:
The cosine of an angle is the x-coordinate of the point where its terminal ray intersects the unit circle. So, we can draw a line at x=-1/2 and see where it intersects the unit circle. That will tell us possible values of θ/2.
We find that vertical line intersects the unit circle at points where the rays make an angle of ±120° with the positive x-axis. If you consider only positive angles, these angles are 120° = 2π/3 radians, or 240° = 4π/3 radians. Since these are values of θ/2, the corresponding values of θ are double these values.
a) The cosine values repeat every 2π, so the general form of the smallest angle will be
... θ = 2(2π/3 + 2kπ) = 4π/3 + 4kπ
b) Similarly, the values repeat for the larger angle every 2π, so the general form of that is
... θ = 2(4π/3 + 2kπ) = 8π/3 + 4kπ
c) Using these expressions with k=0, 1, 2, we get
... θ = {4π/3, 8π/3, 16π/3, 20π/3, 28π/3, 32π/3}
