3.10
1.
(a)
Find the intersection of and
. Then
implies
. Thus these two curves intersects at
and
.Now think of this figure's are as a sum of
.Cut this figure by the line perpendicular to
-axis. Then the width is given by the right-hand curve
the left-hand curve. The hight is given by the
. Thus,
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This figure is not differentiable at
. So, we integrate from
to
and double the value.Cut the figure by the rectangle with small width. Then the area of the rectangle is given by
and
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2.
(a)
Cut this figure by the plane perpendicular to the axis of rotation. Then its cross section becomes a shape called a washer.
implies
.Then
(b)
The graph of this function is called a cycloid.The intersection with the axis is when
and
. When this figure is rotated around the
axis and the rotating body is cut by a plane perpendicular to the
axis, the cross-sectional area is
. If you add a little thickness
to this, its volume will be
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3.
(a)
The graph of
is called asteroid.Now parametrize this function. Then
.
Then we calculate the length of the section
. Then multiply by 4. A part of curve
is given by
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(c)
is symmetric with
-axis and,
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