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Show that the area under the curve y=f(x) for 0<=x<=a is twice the area between the curve y=f(x) and the line ay=f(a)x between the points(0,0) and (a,f(a)).

2006-08-28 06:19:23 · 4 answers · asked by dhufiweioq j 1 in Science & Mathematics Mathematics

4 answers

It's not. Suppose y = f(x) = x, and suppose a = 6.

The area under the curve y = f(x) for the interval (0,6) is
A = int[f(x) dx] = int(x dx) = (1/2) x^2 = 36/2 = 18

The line ay = f(a)x is 6y = 6x (since f(a) = 6), or y = x.

The area under that line between (0,0) and (6,6) is (1/2)(6^2) = 18.

In this counterexample, the curve y = f(x) and the line ay = f(a)x
are the same, so the difference between the two is zero.

2006-08-28 07:01:27 · answer #1 · answered by bpiguy 7 · 1 0

Is f(x)=y just some curved function which is unrelated to your linear function?

kindly clarify ay=f(a)x? did you mean f(x)=ay? ie: f(x) is a straight line.

2006-08-28 13:59:38 · answer #2 · answered by Curious 2 · 0 0

f(a) does not necessarily equal "a". it could be that f(a) = 7a + 3

2006-08-31 13:45:08 · answer #3 · answered by leobloom 1 · 0 0

what differential does it make?

2006-08-28 13:21:32 · answer #4 · answered by gnyla 2 · 0 0

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