Sunday, November 16, 2014

The arc of the parabola y=1/4(x-2)^2 + 1 from the point (-2,5) to the point (4,2).length of arc of the graph of a function addtional applications...

We'll use the following formula to calculate the length of
the arc of the graph of
parabola:


b


`int`
sqrt[1+|f'(x)|^2]dx


a


Therefore,
we need to determine the derivative of the function, using the quotient
rule:


f'(x) =
-8(x-2)/16(x-2)^4


f'(x) =
-1/2(x-2)^3


The arc length of of f from x = -2 to x = 4
is:


4                                           
4


`int` sqrt[1 + 1/4(x-2)^6]dx  = `int` {sqrt[(x-2)^6 +
1]}dx/2(x-2)^3


-2                                       
-2


To calculate the definite integral above, we'll use the
following formula:


`int` rdt/t = r - a*ln|(a+r)/t|, where r
= sqrt (t^2 + a^2)


If t = (x-2)^3 and a = 1, we'll
have:


`int` {sqrt[(x-2)^6 + 1]}dx/2(x-2)^3 =
(1/2)*{sqrt[(x-2)^6 + 1] - ln|{1+sqrt[(x-2)^6 + 1]}/(x-2)^3|} +
C


To evaluate the definite integral, we'll use Leibniz
Newton formula:


4


`int`
{sqrt[(x-2)^6 + 1]}dx/2(x-2)^3= F(4) -
F(2)


-2


F(4) =
(1/2)*{sqrt[(2)^6 + 1] - ln|{1+sqrt[(2)^6 +
1]}/(2)^3|}


F(4) = (1/2)*[sqrt65 -
ln|(1+sqrt65)/8|]


F(4) =
(1/2)*(8.062-0.123)


F(4) =
3.969


F(-2) =  (1/2)*{sqrt[(-4)^6 + 1] - ln|{1+sqrt[(-4)^6
+ 1]}/(-4)^3|}


F(-2) =
32.003


4


`int` {sqrt[(x-2)^6 +
1]}dx/2(x-2)^3=28.034


-2


The
arc length of of y = 1/4(x-2)^2 + 1, from x = -2 to x = 4 is of
28.034.

No comments:

Post a Comment

What is the meaning of the 4th stanza of Eliot's Preludes, especially the lines "I am moved by fancies...Infinitely suffering thing".

A century old this year, T.S. Eliot's Preludes raises the curtain on his great modernist masterpieces, The Love...