00:01
Okay, so we have this function, f of x, which is defined as x squared minus 5x over x squared minus 25, if x is not equal to 5, and 1, if x is equal to 5, and we want to try and see, or explain why this is discontinuous at 5.
00:19
So we should try and find the limit as x tends to 5 of f of x, and then we should compare this with f evaluated at 5.
00:29
So if we want to take this limit, we need to try and work with this part of the function, x squared minus 5x over x squared minus 25.
00:40
Now if you just take x going to 5, then we're in a bit of trouble because this goes to 0 and this goes to 0.
00:46
So firstly, we need to play around with this expression a bit.
00:50
So if we take a factor of x out of the top, we end up with x times x minus 5...