An Interesting Exponential Equation

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  • เผยแพร่เมื่อ 27 ม.ค. 2025

ความคิดเห็น • 6

  • @Blaqjaqshellaq
    @Blaqjaqshellaq หลายเดือนก่อน +4

    If you include complex solutions, there's also x=[ln(phi)+i*(2*n+1)*pi]/[ln(2)-ln(3)], phi being the golden ratio and n being any integer.

    • @Wrest_1349
      @Wrest_1349 หลายเดือนก่อน +1

      Please share your resolution

    • @Blaqjaqshellaq
      @Blaqjaqshellaq หลายเดือนก่อน

      @@Wrest_1349 e^x can also equal -phi/[ln(2)-ln(3)], ln(-1)=i*(2*n+1) and ln(-phi)=ln(phi) + ln(-1).

  • @1234larry1
    @1234larry1 22 วันที่ผ่านมา

    Seems like if you intended to check the solution into the equation, then using common log would be easier than the natural log, since you can change the base.

  • @Foamea45
    @Foamea45 หลายเดือนก่อน

    You overcomplicated this problem.The first thing was right,you divide by 9^x but you write (4/9)^x as [(2/3)^x]^2 and substitute 2/3 as let's say a,but a>0 because an exponential is always positive.Then you have a quadratic in the variable you chose(for me it is a^2+a-1=0) and the solutions are(-1±5^0.5)/2 and since a^0,5 is approximately 2.23 and a is strictly positive we wil chose the +delta root. then we write a as (2/3)^x and x is log in base 2/3 of (-1+5^0,5)/2 ,the same answer,shorter path.

  • @zawatsky
    @zawatsky หลายเดือนก่อน

    3^2x-2^2x-3^x*2^x=0. 3^x:=a, 2^x:=b, a²-2ab-b²=0. (a+b)²=2b²⇔a+b=√2b, но b=2^x⇒√2b=2^(x+½). 2^x+3^x=2^x*(1+(½)^x)=2^(x+lb(1+(½)^x)).⇔x+½=x+lb(1+(½)^x)⇔lb(1+(½)^x)=½⇔√2=1+(½)^x⇔(½)^x=√2-1=1/(2^x)⇔2^x=1/(√2-1)⇔2^(-x)=√2-1⇔-x=lb(√2-1)⇔x=-lb(√2-1). Жаль, что не просто √2, но наверняка можно упростить ещё...