00:01
So today we're looking at complex.
00:04
And given the two functions, f of x, equals x divided by x plus and g of x, and plus two divided by x.
00:13
And so a last sign composed, and this is equal to f of g of x.
00:22
So we substitute g into f, wherever we see an x occur.
00:27
So we have 2 over x, all divided, and 2 over x plus 3.
00:35
Now we can simplify the denominator, and that becomes plus 3x divided by x and so what we get is 2 over x multiplied by the reciprocal of this which is x plus 3x we see that the x is cancelled and what we get is 2 over 2.
01:01
Now because we have 2 plus 3x under the denominator we see that when x is equal to minus 2 third the division by 0 is going to occur.
01:11
What we have is the middle name with the real numbers, but without the number minus two thirds.
01:21
We're going to find g composed with f, which is equal to g of f, with x, so we're substituting f into g, and that is equal to 2, divided by f, which is x over x plus 3.
01:39
And it's simple to calculate, it's just 2 times x plus 3 over x.
01:45
The reciprocal of this.
01:48
And we notice we have x under the denominator, so our function is undefined when x is equal to 0...