Early differentiation question help please
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Early differentiation question help please

[From: ] [author: ] [Date: 11-11-11] [Hit: ]
First you have to find the intersection points of x² and x+2. Set them equal to each other;x² = x + 2x² - x - 2 = 0(x - 2)(x + 1) = 0x = 2, x = -1So when x=-1 and x=2, x² intersects with x+2.Evaluate y for each of these values to find the specific points. These will be used for finding the equation of the tangent lines.......
Find the coordinates of the point of intersection of the tangents to the graph of y = x ^ 2 at the points at which it meets the line with equation y = x + 2.

Can anyone guide me step by step i hjave no clue, i dont even understand the question!! tanks

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The question is asking you to find the point at which two tangent lines intersect. These two lines are the tangents of y = x² when y intersects with y=x+2.

First you have to find the intersection points of x² and x+2. Set them equal to each other;
x² = x + 2
x² - x - 2 = 0
(x - 2)(x + 1) = 0
x = 2, x = -1

So when x=-1 and x=2, x² intersects with x+2.
Evaluate y for each of these values to find the specific points. These will be used for finding the equation of the tangent lines.
y = x² = (-1)² = 1
(-1, 1)
y = x² = (2)² = 4
(2, 4)

Find the equations of the tangent lines at these two points. For this, you need to find the derivative of y=x², which you should know by now is the slope for all x:
dy/dx = 2x

Plug in -1 to find the slope of the tangent line at x=-1:
2(-1) = -2

Now plug in 2 to find slope of tangent at x=2:
2(2) = 4

Use the point-slope formula to find the equations of the tangent lines:
y - y1 = m(x - x1),
where (x1,y1) is the coordinate point and m is the slope (the value of the derivative at each x value).

tangent line at x=-1:
y - 1 = -2(x - (-1))
y = -2x - 1

tangent line at x=2:
y - 4 = 4(x - 2)
y = 4x - 4

Now find the intersection point of the two tangent line by setting them equal to each other:
-2x - 1 = 4x - 4
-6x = -3
x = 1/2

Plug x=1/2 into either tangent line equation. I'll do it with both to check.
-2(1/2) - 1 = -1 - 1 = -2
4(1/2) - 4 = -2

Answer:
(x, y) = (1/2, -2)

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So first differentiate y = x ^ 2 to get y=2x ( you know that this is the tangent formula for y = x ^ 2)
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