tangent equations and sketches plZ HELP!!

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xkouki

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Nov 12, 2005
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Sketch the graphs of the two equations y=x^2 and y= -x^2 + 6x - 5, and sketch the two lines that are tangent to both graphs. Find the equations of these lines...



Please help!!!
 
On which part are you stuck? You can draw the graphs, right? And find the derivates (which will provide the slope information)? Then what?

Please reply with specifics. Thank you.

Eliz.
 
well that's how i was doing it and then my teacher started talking about you have to make the slopes equal to eachother or something because the tangent lines dont touch the slopes, she confusedme!!!
 
So she said (as did I) that, once you've done the graphs, you have to find the derivatives so you can find the slopes...?

Since the slopes of the tangent lines are given by the derivatives at the points at which the tangents touch (slopes aren't "touched" by anything; they're just numbers), you must have misunderstood her regarding this topic. However, since I wasn't there, I'm afraid I have no way of knowing what she might have said, so I can't clarify it. Sorry. You might want to try consulting with her again.

Meanwhile, what did you get for your derivatives?

Eliz.
 
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