Leah Posted September 15, 2013 Report Share Posted September 15, 2013 Hey everyone,I already spend a couple of hours on this question but I cant find a solution. I also looked up everything related to inverse functions, did examples,... Could one of you probably help me with this question. It is quite urgent because I have a periodic coming up on Tuesday. I hope you can help me and thanks in advance.It is the first question, everything else is clear!Leahrevision.rtf Reply Link to post Share on other sites More sharing options...
ninale Posted September 15, 2013 Report Share Posted September 15, 2013 well in order to have an inverse , the function has to be one-to one. for example a quadratic function lets say f(x)=(x-1)(x-3) if you plot it, in order to have an inverse you have to choose either x>2 or x<2 (because you need a one to one) so in this exercise if you plot f(x) you will see a max at 2.44 ((root 6) because that's where the first derivative has a zero)so in order to be one to one choose the area x>2.44 (root6) Reply Link to post Share on other sites More sharing options...
ninale Posted September 15, 2013 Report Share Posted September 15, 2013 also if in your test a question asks you to find the inverse of a quadratic function let's say f(x)=(x-1)(x-3) , x>2, you MUST write it first in vertex form , otherwise you cannot find the inverse... Reply Link to post Share on other sites More sharing options...
Leah Posted September 15, 2013 Author Report Share Posted September 15, 2013 Ok that part is clear now, but for a) I'm still clueless if Im honest. I know that I have to change x to y and then put x on one side. However, I never get to 12-2x²/(x²+6)². Do you knw how get there?Oh really? That's good to know because we never did it that way. Reply Link to post Share on other sites More sharing options...
ninale Posted September 15, 2013 Report Share Posted September 15, 2013 well......you need to find the first derivative not the inverse...in the first question... Reply Link to post Share on other sites More sharing options...
Leah Posted September 15, 2013 Author Report Share Posted September 15, 2013 well......you need to find the first derivative not the inverse...in the first question...That explains why we all didnt get the questions because we never ever did derivatives before and our teacher often uses the notation f' for the inverse function... Reply Link to post Share on other sites More sharing options...
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