k= 3x^2 - x^3

Quadratic equations and inequalities, variation equations, function notation, systems of equations, etc.
Nats
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Joined: Mon Aug 19, 2013 11:14 am
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k= 3x^2 - x^3

The equation k= 3x^2 - x^3 is satisfied by one value for x between -2 and 4. what can be said about the value of k?

buddy
Posts: 197
Joined: Sun Feb 22, 2009 10:05 pm
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Re: k= 3x^2 - x^3

The equation k= 3x^2 - x^3 is satisfied by one value for x between -2 and 4. what can be said about the value of k?
think of this like 2 functions: Y1 = 3x^2 - x^3 & Y2 = k. look at the graph of Y1 and think abt where you'd only get ONE number for x going with a number for y = Y2 = k. (but you probably need calculus for this, too????)

Nats
Posts: 18
Joined: Mon Aug 19, 2013 11:14 am
Contact:

Re: k= 3x^2 - x^3

The equation k= 3x^2 - x^3 is satisfied by one value for x between -2 and 4. what can be said about the value of k?
think of this like 2 functions: Y1 = 3x^2 - x^3 & Y2 = k. look at the graph of Y1 and think abt where you'd only get ONE number for x going with a number for y = Y2 = k. (but you probably need calculus for this, too????)
x = -2 -1 0 1 2 3 4
y = 20 -2 0 2 4 0 -16

still dont understand the value of k

buddy
Posts: 197
Joined: Sun Feb 22, 2009 10:05 pm
Contact:

Re: k= 3x^2 - x^3

x = -2 -1 0 1 2 3 4
y = 20 -2 0 2 4 0 -16

still dont understand the value of k
what did you get for a graph? what heights have 2+ x's that give that height? what heights match only 1 x? copy off the picture.