Guest KAPOWW!! Posted September 2, 2011 Report Share Posted September 2, 2011 Yo guys! I did this in my tenth and due to a years gap I can't recollect the correct technique, care to guide me? P.S. No links please, Thanks! Sorry if its an inconvenience! Reply Link to post Share on other sites More sharing options...
dessskris Posted September 2, 2011 Report Share Posted September 2, 2011 I've heard that this in Maths St is more difficult than in Maths HL this is how I usually do it though: 1. look for points where the graph cuts the x-axis. this will become a vertical asymptote (|). 2. if there is a vertical asymptote, it will become a zero. 3. if there is a horizontal asymptote (---), it will stay as an asymptote but in a different position (1/y) 4. split the graph to sections based on the shapes. also split if it's passed through the x-axis. look at them one by one, section by section. 5. for any point where y=1 or -1, that point will stay there. 6. just imagine the inverse and try to connect them. I suck at explaining :/ I could've explained better if there was a question example but say if y=0.5, it would become 2. if y=10 then it would be very close to the x-axis. imagine it... if you don't get it ask again. or I hope someone could explain this better. Reply Link to post Share on other sites More sharing options...
jess1ca Posted September 2, 2011 Report Share Posted September 2, 2011 (edited) Yo guys! I did this in my tenth and due to a years gap I can't recollect the correct technique, care to guide me? P.S. No links please, Thanks! Sorry if its an inconvenience! Well what I do is switch the x and the y values and then solve for y. For example Find the inverse of f(x)=2x-3 1) Replace f(x) with y y = 2x-3 2) Switch the x's and y's x= 2y-3 x+3=2y (x+3)/2 =y Therefore f-1(x) =(x+3)/2 However don't forget that the inverse of a function isn't always a function because a function has only one value of y for every value of x. (For example, the inverses of quadratic functions are not functions). So if you are asked to find the inverse function, you have to set restrictions on your inverse to make it a function. To visualize inverses: Remember to graph the inverse of a function you reflect it across the line y=x. The x and y values of the inverse will be switched. If (1,0) is a point on f(x), (0,1) is a point on f-1(x). Sorry if that didn't make sense.... :/ Edited September 2, 2011 by SmilingAtLife:) Reply Link to post Share on other sites More sharing options...
The Economist Posted September 2, 2011 Report Share Posted September 2, 2011 Actually the method I know is the same as SmilingAtLife's I just first solve in terms of x and then switch y for x. Usually finding the inverse of a function is pretty easy and you may find only 4-5 tricky examples but the above method always works Reply Link to post Share on other sites More sharing options...
dessskris Posted September 2, 2011 Report Share Posted September 2, 2011 (edited) oh my God...I thought you were talking about the inverse graph reciprocal function -________-sorry! hehe -____-*geez what's wrong with me today -____- Edited September 2, 2011 by Desy Glau Reply Link to post Share on other sites More sharing options...
Guest KAPOWW!! Posted September 2, 2011 Report Share Posted September 2, 2011 Thanks guys that was really fast and helpful too! Reply Link to post Share on other sites More sharing options...
Guest KAPOWW!! Posted September 2, 2011 Report Share Posted September 2, 2011 I've heard that this in Maths St is more difficult than in Maths HL this is how I usually do it though: 1. look for points where the graph cuts the x-axis. this will become a vertical asymptote (|). 2. if there is a vertical asymptote, it will become a zero. 3. if there is a horizontal asymptote (---), it will stay as an asymptote but in a different position (1/y) 4. split the graph to sections based on the shapes. also split if it's passed through the x-axis. look at them one by one, section by section. 5. for any point where y=1 or -1, that point will stay there. 6. just imagine the inverse and try to connect them. I suck at explaining :/ I could've explained better if there was a question example but say if y=0.5, it would become 2. if y=10 then it would be very close to the x-axis. imagine it... if you don't get it ask again. or I hope someone could explain this better. The effort counts! Reply Link to post Share on other sites More sharing options...
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