(a) The curve with equation y2 = x3 + 3x2 is called the Tschirnhausen cubic. Find an equation of the tangent line to this curve
at the point (1, 2). y = 9 4x− 1 4(b) At what points does this curve have horizontal tangents? (x, y) = (smaller y-value) (x, y) = (larger y-value)(c) Illustrate parts (a) and (b) by graphing the curve and the tangent lines on a common screen
1 answer:
Answer:
(a) y = 9/4x -1/4
(b) (-2, -2), (-2, 2)
(c) see below
Step-by-step explanation:
(a) The derivative can be found from ...
2y·y' = 3x² +6x
At (x, y) = (1, 2), this is ...
4y' = 9
y' = 9/4
so the equation of the tangent is ...
y = (9/4)(x -1) +2
y = (9/4)x -1/4
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(b) At y' = 0, we have ...
0 = 3x² +6x = 3x(x +2)
This says y' = 0 at x=0 or x=-2. (x = 0 is an extraneous solution.)
At x = -2, we have ...
y² = (-2)³ +3(-2)² = -8+12 = 4
y = ±2
So, the horizontal tangent points are (x, y) = (-2, ±2).
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Answer:
The side closest to P is the side that is on the same side of the angle bisector as P.
Step-by-step explanation:
The angle bisector is the line containing all the points equidistant from the sides of the angle. Points on one side of the angle bisector are closer to the angle side that is on that side of the angle bisector.
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The attached diagram shows the angle bisector as a dashed line. A couple of different locations for P are shown (P1 and P2). Apparently, we're concerned here with the distance from P along the perpendicular to each side of the angle. For P2 (on the left side of the angle bisector), it may be clear that the left perpendicular is shorter than the right one. Likewise, for P1, the right perpendicular will be shorter.
