00:01
Let r be the region bounded by the following curves.
00:04
Y equal to x over square root of x plus 1, y equal 0, and x equal to 8.
00:10
Now the curves x over square root of x plus 1 and y equals 0, they intersect whenever x over the square root of x plus 1, this is equal to 0, or that means x is 0.
00:32
And so from here we can say that the region is in between 0 and 8.
00:39
Over here, we have the area of the region shaded in blue.
00:48
From here, we can see that the area of the region will be equal to the integral from 0 to 8 of x over the square root of x plus 1, which is the upper function, minus the bottom function, which is 0, dx.
01:09
And then this will simplify to the integral from 0 to 8 of x over the square root of x plus 1 dx.
01:19
Now we are ready to integrate.
01:23
Because the denominator has the form a plus b to the n, where n here is one -half, we then use formula 5 of appendix b, which is, comparing this formula and the integral representing a we have a equal to 1 b equal to 1 and n equal to 1 half and so using formula 5 we have 1 over 1 squared times negative 1 over n which is 1 half minus 2 times x plus 1 to the 1 half minus 2 plus 1 over 1 half minus 1 times x plus 1 raise to 1 half minus 1.
02:31
This evaluated from 0 to 8.
02:36
Now simplifying we have this part right here is just 1.
02:40
So we have negative 1 over negative 3 halves.
02:48
Times x plus 1 to the negative 3 halves plus 1 over that's negative 1 half times x plus 1 raised to negative 1 half evaluated from 0 to 8.
03:05
Simplifying further we get positive 2 over 3 times x plus 1 raised to positive 3 halves minus 2 times x plus 1 raise to positive 1 half evaluated from 0 to 8 now when x is 8 we have 2 over 3 times 8 plus 1 raise to 3 halves minus 2 times 8 plus 1 raised to 1 half and when x is 0 we have 2 over 3 times 0 plus 1 to the 3 halves minus 2 times 0 plus 1 raise to 1 half.
03:49
This then gives us 2 over 3 times 9 to the 3 halves minus 2 times 9 to the 1 half minus 2 over 3 times 1 to the 3 halves plus 2 times 1 to the 1 half...