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    Need some help with the following question. I don't know how to do it

    3^x e^(7x+2)=15

    mm it is supposed to be e^(7x+2) not sure how you latex that.

    Any help would be appreciated
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    My knowledge only extends to C2. I'm trying to understand concepts now. Dif/int are easy but understanding them is problematical. Shouldn't be too hard.
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    (Original post by MathMeister)
    My knowledge only extends to C2. I'm trying to understand concepts now. Dif/int are easy but understanding them is problematical. Shouldn't be too hard.
    Your point is?
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    (Original post by Super199)
    Need some help with the following question. I don't know how to do it

    3^x e^(7x+2)=15

    mm it is supposed to be e^(7x+2) not sure how you latex that.

    Any help would be appreciated
    Does this help:

    3^{x}=e^{ln(3^{x})}=e^{xln(3)}
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    (Original post by rayquaza17)
    Does this help:

    3^{x}=e^{ln(3^{x})}=e^{xln(3)}
    Nope I honestly don't know what do with that.
    Can I just take ln of both side and use log laws?
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    (Original post by Super199)
    Your point is?
    I just wanted to comment :/ I hope you do well in your exams.
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    (Original post by MathMeister)
    I just wanted to comment :/ I hope you do well in your exams.
    Haha fair enough. Stop procrastinating and go do some C1
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    (Original post by MathMeister)
    Doing c2 at the mo. C1 doesn't test me much. I've basically done it all tbh.
    Are you doing S1 or M1 next year?
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    I'm doing C1,C2,S1- FP1, M1 and M2. (I think) Or instead it will be S2 rather than M2.
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    (Original post by Super199)
    Any help would be appreciated
    Okay so 3^x e^{7x+2} = 15

    I would natural log both sides, so you have:

    \ln(3^x e^{7x+2}) = \ln(15)

    Use your rules of logarithms to get this:

    \ln(3^x) + \ln(e^{7x+2}) = \ln(15)

    I'm sure you can do the rest bearing in mind the logarithm rule of \ln(a^b) = b\ln(a) and rearranging.
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    (Original post by Super199)
    Need some help with the following question. I don't know how to do it

    3^x e^(7x+2)=15

    mm it is supposed to be e^(7x+2) not sure how you latex that.

    Any help would be appreciated
    ln(3^x) + ln(e^(7x+2) = ln15

xln3 + 7x + 2 = ln15
    as lne = 1 and ln(e^(7x+2)) = (7x+2)lne

    xln3 + 7x = ln15 - 2

x(ln3 + 7) = -2 + ln15

x = (-2 + ln15)/(ln3+7)

    that's what I'd do anyway
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    (Original post by CTArsenal)
    Okay so 3^x e^{7x+2} = 15

    I would natural log both sides, so you have:

    \ln(3^x e^{7x+2}) = \ln(15)

    Use your rules of logarithms to get this:

    \ln(3^x) + \ln(e^{7x+2}) = \ln(15)

    I'm sure you can do the rest bearing in mind the logarithm rule of \ln(a^b) = b\ln(a) and rearranging.
    Ahh got it. Didn't spot the 2nd step :rolleyes: . Thanks
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    (Original post by shutupem)
    ln(3^x) + ln(e^(7x+2) = ln15

xln3 + 7x + 2 = ln15
    as lne = 1 and ln(e^(7x+2)) = (7x+2)lne

    xln3 + 7x = ln15 - 2

x(ln3 + 7) = -2 + ln15

x = (-2 + ln15)/(ln3+7)

    that's what I'd do anyway
    Yh that's what I got with a bit of guidance . Cheers
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    (Original post by Super199)
    Need some help with the following question. I don't know how to do it

    3^x e^(7x+2)=15

    mm it is supposed to be e^(7x+2) not sure how you latex that.

    Any help would be appreciated
    e(7x + 2)

    e[sup](7x + 2)[/sup

    just type in the above & put the missing square bracket...
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    (Original post by shutupem)
    ln(3^x) + ln(e^(7x+2) = ln15

xln3 + 7x + 2 = ln15
    as lne = 1 and ln(e^(7x+2)) = (7x+2)lne

    xln3 + 7x = ln15 - 2

x(ln3 + 7) = -2 + ln15

x = (-2 + ln15)/(ln3+7)

    that's what I'd do anyway
    Full solutions should be a last resort.
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    (Original post by Super199)
    Need some help with the following question. I don't know how to do it

    3^x e^(7x+2)=15

    mm it is supposed to be e^(7x+2) not sure how you latex that.

    Any help would be appreciated
    sorry if this is terribly silly of me but are you solving for x?
    usually in that case i take ln on both sides and use the properties! but im not getting e^(7x+2)...
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    (Original post by sharvarivadeyar)
    sorry if this is terribly silly of me but are you solving for x?
    usually in that case i take ln on both sides and use the properties! but im not getting e^(7x+2)...
    I'm not sure what your question is? If you are referring to the e^(7x+2) bit underneath the question, I was saying that I couldn't type it in properly. The answer isn't that
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    (Original post by Super199)
    I'm not sure what your question is? If you are referring to the e^(7x+2) bit underneath the question, I was saying that I couldn't type it in properly. The answer isn't that
    lolol nvm got it xD sorry!
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    (Original post by Super199)
    Need some help with the following question. I don't know how to do it

    3^x e^(7x+2)=15

    mm it is supposed to be e^(7x+2) not sure how you latex that.

    Any help would be appreciated
    are you doing work for your next year?
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    (Original post by Ilovemaths96)
    are you doing work for your next year?
    Yup. I have 10 weeks off, got 6 left but I have been fooling around for half of the time. Wbu?
 
 
 
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