You can plot the two functions here:
http://www.coolmath.com/graphit/index.html
You can visibly see where they intersect. You can also do it with a little calculus:
Let y1 = x, y2 = 2^x, y = y2 - y1.
y1 and y2 will intersect when y1 = y2, or when y = 0.
y = y2 - y1 = 2^x - x = e^(x*ln2) - x
But notice: dy/dx = ln2*e^(x*ln2) - 1
When dy/dx = 0, ln2*e^(x*ln2) -1 = 0, so
e^(x*ln2) = 1/ln2
x*ln2 = ln(1/ln2)
x = ln(1/ln2)/ln2
Also, notice that d2y/dx2 = (ln2)^2*e(x*ln2), and when x = ln(1/ln2)/ln2, d2y/dx2 is positive. Thus, we can conclude that y is at a minimum at x = ln(1/ln2)/ln2.
But when x = ln(1/ln2)/ln2, then y = 2^x - x is positive. Since this is a minimum, we can conclude that y is always positive, and thus that 2^x is always larger than x. Thus, they don't intersect.
2007-01-13 16:20:41
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answer #1
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answered by rozinante 3
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You should create an x,y chart to graph the functions. Then you'll see that they intersect at x=0 and x=1/2.
2007-01-14 00:30:15
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answer #2
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answered by Dalonna 2
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The two graphs do not intersect.
y = x is a straight line that has a slope o1 and passes through the origin.
y= 2^x is always positive and at - infinity and is aymptotic to the x-axis until it swings upward crossing the y axis at the oint (0,2) and shoots rapidly upwards toward + infinity. It is always above the line y=x. That should be sufficient for you to draw a rough sketch.
2007-01-14 00:37:32
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answer #3
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answered by ironduke8159 7
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no both of them are diffirent
on is a line
and the other on is not
y=x is line
and y=2_____x is i belive a inverse s curve
i have a graphing caculator
and so i am pretty sure i am right
2007-01-14 00:23:49
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answer #4
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answered by rahul g 1
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There is no point of intersection as the value of y in y = 2^x is always greater than the value of y in y=x.
2007-01-14 00:16:13
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answer #5
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answered by thenextchamp919 2
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NOT POSSIBLE..
just make the graph.. You'll find the answer.. Why are you so lazy??
2007-01-14 00:45:47
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answer #6
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answered by andru 2
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NOT POSSIBLE.
2007-01-14 00:17:05
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answer #7
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answered by freddelorme35 3
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