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Math Help - e^...

  1. #1
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    e^...

    f(x)= e^(3x+1) -2
    the curve y=f(x) meets the y-axis at the point P and the x-axis at the point Q
    find the exact coordinates of P and Q
    ive tried to work out P and Q by taking x=0 and y=0 respectively is this right? it just doesnt seem like much working out for the amount of marks it's worth. can someone please show me their working for this question?
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  2. #2
    MHF Contributor red_dog's Avatar
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    x=0\Rightarrow y=e-2\Rightarrow P(0,e-2)
    y=0\Rightarrow e^{3x+1}=2\Rightarrow 3x+1=\ln 2\Rightarrow\displaystyle x=\frac{\ln 2-1}{3}\Rightarrow Q\left(\frac{ln 2-1}{3},0\right)
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  3. #3
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    Quote Originally Posted by red_dog View Post
    x=0\Rightarrow y=e-2\Rightarrow P(0,e-2)
    y=0\Rightarrow e^{3x+1}=2\Rightarrow 3x+1=\ln 2\Rightarrow\displaystyle x=\frac{\ln 2-1}{3}\Rightarrow Q\left(\frac{ln 2-1}{3},0\right)
    oh, i did get it right! ok thanks...makes me feel better to have it confirmed!
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