00:01
So, here according to the question, the integral given to us is integration from limits 9 to 16, 10 square root of x upon x minus 4 dx and we have to find its value using substitution method.
00:17
So, what we will do here, we will first of all let x is equal to t square.
00:22
Ok.
00:22
So, if x is equal to t square, then the value of dx will be equal to 2t multiplied by dt.
00:29
Ok.
00:29
So, we will change the limits too.
00:31
So, if x is equal to 9, then the value of t when x is equal to 9, the value of t will be 3.
00:40
Ok.
00:40
And when x is equal to 16, the value of t will be square root of 16 which is 4.
00:47
Ok.
00:48
So, the integral i will be now from limits 3 to 4 and 10 square root of x will be equal upon x minus 4 that means t square minus 4 and the value of dx is 2t dt.
01:02
Ok.
01:03
So, here it will become t square and 10 multiplied by 2 is 20.
01:07
So, we can take 20 outside because it is constant and integration 3 to 4, we have here t square dt upon t square minus 4.
01:16
So, now how will we solve it? 20 integration 3 to 4.
01:20
Now, we will write here t square, then we will write here minus 4 and plus 4.
01:26
So, minus 4 plus 4 will be again 0 and t square is as it is.
01:31
And here it is dt upon t square minus 4.
01:34
Now, we will separate the numerator and denominator like t square minus 4 upon t square minus 4 and plus 4 upon t square minus 4.
01:43
Ok.
01:43
So, the integration i value will be first of all 20, 20 integration from 3 to 4 and t square minus 4 upon t square minus 4 will be 1.
01:56
So, only integration of dt here.
01:58
Ok.
01:58
Then we have plus 20 and this 4 can be taken outside because it is constant.
02:05
So, 20 multiplied by 4 is 80 and integration from 3 to 4, we have dt upon t square minus we can write here 4 as 2 whole square.
02:16
Ok.
02:17
So, now the integration of dt is t.
02:19
So, 20 here t and limits are from 3 to 4 plus 80 here and the integration we know that the integration of dx upon x square minus a square.
02:31
Ok...