00:01
Hello students, the given function is f of x equal to 1 by minus bx plus 5.
00:06
Here we have to derive the first derivative of f at x equal to 5.
00:13
So, first we have to compute f of 5 plus h.
00:23
Here we have to substitute x equal to 5 plus h in f of x.
00:35
Therefore, f of 5 plus h equals 1 by minus 3 into 5 plus h plus 5.
00:48
Therefore, it will be 1 by minus 15 minus 3 h plus 5.
00:55
Therefore, f of 5 plus h equals 1 by minus 3 h minus 10.
01:09
Next, we have to find f of 5.
01:20
To find f of 5, we have to substitute x equal to 5 in f of x.
01:31
Therefore, f of 5 becomes f of 5 equals 1 by minus 3 into 5 plus 5, which gives f of 5 equal to 1 by minus 10.
01:54
Therefore, we know that the derivative of the function, that is the given function is f of x at x equal to a is given by the formula that f dash of a equals limit h tends to 0 f of a plus h minus f of a divided by h.
02:41
Therefore, here we have to find the derivative of the function at x equal to, at a equal to 5.
02:48
Therefore, the derivative of the function f of x at x equal to 5 is, here we have to replace a by x, that is 5.
03:16
Therefore, it will be f dash of 5 equals limit h tends to 0...