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    Does anyone have a foolproof method for working out range and domain of any function? Even though theyre only 1 or 2 marks, they are the hardest questions in C3 and Im aiming for an A*
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    (Original post by Nayzar)
    Does anyone have a foolproof method for working out range and domain of any function? Even though theyre only 1 or 2 marks, they are the hardest questions in C3 and Im aiming for an A*
    For domain, think of any values that make the function not work... no real easy/quick way of doing this, but all you need to know is what usually breaks a function simpler than the one you have, and how that relates to what you have. (Eg if you're asked to find the domain of ln(2x+5), you know that the 'simpler' function lnx has a domain of x>0, so you know that 2x+5 needs to be >0.

    For the range.. put in large values of x like 100000 and -100000 if it makes sense to and see what happens. Skech the graph if possible and try to find the range that way.
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    (Original post by Nayzar)
    Does anyone have a foolproof method for working out range and domain of any function? Even though theyre only 1 or 2 marks, they are the hardest questions in C3 and Im aiming for an A*
    I've written two, very detailed, posts over the past year or so that explains domains and ranges - if you could just take a few minutes to sit down and read them, it'll be worth your while (hopefully).

    Post 1 and Post 2.
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    Fanks goyz
 
 
 
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