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logarithm question, PLEASE HELP, i'd appreciate it!?

Solve the equation ex − e−x = 2.

5 Answers

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  • 9 years ago
    Favorite Answer

    ex - e-x = 2

    ex - 1/ex = 2

    lcm

    e2x - 1 = 2ex

    e2x - 2ex -1 =0

    put ex =t

    t^2 -2t - 1 = 0

    t = {-(-2) +- √(-2^2 - 4(1)(-1))}/2(1)

    t = {2 +- √ (4+4)}/2

    t = 1+- √2

    so

    ex= 1 + √2 and ex = 1-√2

    so x = ln (1+√2)

    and

    x = ln (1-√2) (neglect this as ln argument cant be negative )

    so answer is x = ln(1+√2)

    x = ln(1+1.414)

    = ln(2.414)

    = 0.88137

  • 4 years ago

    (assets :-- log a N =z so N=a^z) log9 27=x 27=9^x (making use of the above assets) 3^3=3^2x by using fact the backside are comparable i.e=3 so equating the powers 3=2x x=3/2 log2 8=y 8=2^y (lower back making use of the valuables) 2^3=2^y lower back base is comparable i.e 2 so equating the powers y=3 log9 27 . log2 8=x*y=3/2*3=9/2

  • Ed I
    Lv 7
    9 years ago

    ex = 2 + e + x

    x = (2 + e + x)/e

    Maybe you meant: e^x - e^(-x) = 2.

    e^(2x) - 1 = 2e^x

    e^2x - 2e^x - 1 = 0

    Let u = e^x

    u^2 - 2u - 1 = 0

    u^2 - 2u = 1

    u^2 - 2u + 1 = 1 + 1

    (e^u - 1)^2 = 2

    e^u - 1 = ± √2

    e^u = 1 ± √2

    u = ln (1 + √2), because u - √2 < 0 and isn't in the domain of ln.

    u = 1 + √2 = e^x

    x = ln (1 + √2)

  • 9 years ago

    If it is e^x-e^(-x)=2

    then let e^x=y

    y^2-2Y-1=0

    y=1+2^(1/2)

    Therefore x=log(1+sqrt(2))

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  • DWRead
    Lv 7
    9 years ago

    Do you mean e^x - e^(-x) = 2?

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