Old Test Questions AnsweredDate: 23 Jan 1995 19:52:49 -0500 From: Cheryl A. Backman Subject: math questions Hi there! I am studying for my course III midterm, which happens to be tomorrow. In reviewing an old chapter test, I've come across two questions that I got wrong and don't understand why. I was wondering if you could please help me with this. Thanks. Here they are: State the largest possible domain such that the given relation is a function (a) f(x)=__2__ x-2 (b) g(x)= __1___ the square root of x-1 For part b, there was an "x" and then an arrow with a "g" over it pointing to the right. I assumed it was g(x). Sorry, I couldn't get the computer to do that or the square root. Thanks again, Michele Date: 24 Jan 1995 01:29:43 GMT From: Dr. Math Subject: Re: math questions Hello there! You want to figure out what numbers make sense to plug in to your functions. In the first one, which I'll write f(x) = 2/(x-2), you can pretty much plug in anything, EXCEPT something which would make you divide by zero. So for what value of x is x-2=0? You're right about the next problem, which sounds like it was written g:x -> 1/Sqrt{x-1}. It can also be written g(x) = 1/Sqrt{x-1}, and here you have the same deal. What numbers can you plug in to this function? Well, again, anything that makes sense. But here it's a little different. You still can't divide by zero, but you also can't take the square root of a negative number. So you'll have to exclude all the x that make x-1 negative or zero. I hope this helps! -Ken "Dr." Math Date: 23 Jan 1995 21:30:34 -0500 From: Cheryl A. Backman Subject: thanks Dr. Math, Thanks again for your response. The explanation made a world of difference! -Michele |
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