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    (Original post by krane)
    Can I just throw a question in here...?

    It's probably really simple, but if the domain of f(x) is x is all real values, how do you work out the range?
    It's for f(x) = e^2x + 3 (on Jan 2010 paper).

    We did this stuff at the end and my notes for then were a mess
    Cheers
    Usually you figure out the smallest possible value of what you have. The smallest value of e^2x is (sort of*) 0, so the range is basically greater than (NOT greater than or equal to) 3.

    *this occurs when x is negative and large.

     e^{2x} > 0 , \text{for all}  x 

\Rightarrow f(x) > 3, \text{for all}  x
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    I did about 2 weeks studying for C1 last year and got an A. I'm doing C2 and S1 studying now for Jan exams. Was supposed to take them last summer but fell ill
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    (Original post by Economi)
    Think about the graph.

    "f(x)= e^x" is always above 0. So with graph transformations, +3 outside the bracket it an increase in the Y value by 3. Because of this the range is now f(x) > 3.

    EDIT: I don't think the domain is all real values. It should be x>3 also? X being the domain.
    domain is actually real values



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    (Original post by Economi)
    Think about the graph.

    "f(x)= e^x" is always above 0. So with graph transformations, +3 outside the bracket it an increase in the Y value by 3. Because of this the range is now f(x) > 3.

    EDIT: I don't think the domain is all real values. It should be x>3 also? X being the domain.
    (Original post by ghobro)
    Usually you figure out the smallest possible value of what you have. The smallest value of e^2x is (sort of*) 0, so the range is basically greater than (NOT greater than or equal to) 3.

    *this occurs when x is negative and large.

     e^{2x} > 0 , \text{for all}  x 

\Rightarrow f(x) > 3, \text{for all}  x
    Thank you both! I didn't think about e^x having a lowest value of 0, so I didn't know what number to put into fx.
    Many thanksss
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    (Original post by krane)
    Thank you both! I didn't think about e^x having a lowest value of 0, so I didn't know what number to put into fx.
    Many thanksss
    e^x cannot be 0 - you may already know that but saying it has a 'lowest value of 0' suggests not.
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    It is hardly difficult to self-teach core 3 for an exam next week. I am teaching myself FP3 and FP2 for the summer.
    Just make sure you truly understand the reciprocal trigonometric functions and things like the chain rule, product rule, quotient rule for differentiation and the integration by parts and substitution. They are the hardest things that appear really, especially when they are mixed together in a question. (As an example of this look at January 2012 Core 3, which I took). So long as you are confident it is very possible to teach yourself the entire module in 7 days.

    EDIT: Look at question 6 specifically
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    Im planning to start c3 revision 7 days before my exam, but its the only exam I have then so I guess its okay?
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    (Original post by raiden95)
    Im planning to start c3 revision 7 days before my exam, but its the only exam I have then so I guess its okay?
    same. 7 days should be enough, and i am saying that after doing no math this year ( except in class). I did the same last year for AS, and i got 300ums - so it is possible, just do pastpapers.
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    (Original post by Ronove)
    e^x cannot be 0 - you may already know that but saying it has a 'lowest value of 0' suggests not.
    Ah right, I mean that it can't be lower than 0!
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    (Original post by krane)
    Ah right, I mean that it can't be lower than 0!
    If you describe it as 'it can't be lower than 0' then it can be 0! It is greater than 0.
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    Good luck with that.
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    (Original post by ghobro)
    It is hardly difficult to self-teach core 3 for an exam next week. I am teaching myself FP3 and FP2 for the summer.
    Just make sure you truly understand the reciprocal trigonometric functions and things like the chain rule, product rule, quotient rule for differentiation and the integration by parts and substitution. They are the hardest things that appear really, especially when they are mixed together in a question. (As an example of this look at January 2012 Core 3, which I took). So long as you are confident it is very possible to teach yourself the entire module in 7 days.

    EDIT: Look at question 6 specifically
    These are C4 material for Edexcel. I just covered the whole of C3 and thought I'd completely forgotten something already, you scared the crap out of me!
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    (Original post by Mr. Ban)
    same. 7 days should be enough, and i am saying that after doing no math this year ( except in class). I did the same last year for AS, and i got 300ums - so it is possible, just do pastpapers.
    Wow 300? I only got 252, but then again I did it with my gcses, hopefully I can get the A*
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    (Original post by Ronove)
    These are C4 material for Edexcel. I just covered the whole of C3 and thought I'd completely forgotten something already, you scared the crap out of me!
    Oh sorry!
    I inadvertently believed you were doing AQA.
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    (Original post by MontanaRC)
    Do you guys think I could be able to pull of finishing the C3 module in 7 days with basic knowledge with all day studying?

    Post your thoughts and experience.

    Oh, and I'm planning to get A - A*
    Possible only if you have no other exams and you have a strong grasp of C1 and C2

    Revise from 9-5, then get 2 hours tutoring from a teacher (5-7pm; to clear any problems you are having), then return to work 8pm-12am

    Do this each day for the next 7 days and you have a chance at the A/A*
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    (Original post by ghobro)
    Oh sorry!
    I inadvertently believed you were doing AQA.
    The OP may well be doing AQA though there's nothing in the first post about it. Just thought I'd share how much of a fright you gave me.
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    I'm doing Edexcel lol
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    (Original post by MontanaRC)
    I'm doing Edexcel lol
    Yes its possible

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