00:01
We're given a curve and we're asked to find the exact length of this curve.
00:05
The curve has the equation x equals 1 3rd square root of y times y minus 3, where y lies in the interval 1 .9.
00:25
So given this equation, we have that, in fact, x is also equal to 1 .3 times y to the 3 halves.
00:43
Minus y to the one half and therefore the derivative of x with respect to y is going to be the derivative of this is one half y to the one half and then minus 1 over 2 y squared of y you can say simply minus 1 half y the negative 1 half and therefore 1 plus d x d y squared this is going to be 1 plus 1 fourth y, and then we have 2 times that is going to be minus 1 half, and then plus 1 4th, y to the negative 1.
01:52
In combining terms, we get 1 4th y plus 1ā2nd, plus 1ā4 y to the negative 1, which can be factored as 1ā2y plus 1ā2.
02:07
Y the negative first squared or sorry this should be y to the one half and then this should also be y to the negative one half there we go and so it calls that the length of this curve is the integral from y equals one to nine of the square root of this expression one half wide of the one half plus one half wide of the negative one half squared, d .y, which is the same as the integral from one to nine of, and then this is going to be the absolute value of one half, y to one half plus one half, why the negative one half...