00:02
Rx is given as 300 minus 225 x plus 5 minus x to find the maximum value we will find the critical point first and critical points are calculated by equating the first derivative to 0.
00:24
So take the first derivative of a constant is 0 minus 225 is a constant d by d x of 1 .1 .225 is a constant d by d x of 1.
00:35
X plus 5 minus d by d x of x so it would be minus 2 to 5 it is 1 by x plus 5 can be written as x plus 5 to the power minus 1 so d by d x of this would be minus 1 then x plus 5 to the power minus 2 and then d by d x of x 1 so it can be written as minus 1 by x 1 by x 1 by x of x 1.
01:03
So it can be written as minus 1 by plus 5 to the power 2.
01:08
So replace this by this way.
01:11
So it would be minus 1 x plus 5 to the power 2.
01:16
Now d by d x of x is 1.
01:20
Simplify this whole expression, it would be minus minus cancelled out so it would be 2 to 5 by x plus 5 square minus 1.
01:31
Now equate the first derivative to 0.
01:37
Here.
01:38
Our first derivative is 2 to 5 by x plus 5 whole square minus 1 equals to 0.
01:44
Minus 1 goes here and becomes positive.
01:47
X plus 5 equals to 1.
01:51
Then by cross multiplication equals to x plus 5 whole square.
01:57
2 to 5 is square of 15.
02:00
So x plus 5 will come out to be 15.
02:04
So x will come out to be 10...