Math Problem Statement

Solve simultanously

Solve simultaneously: ln(x) + ln(y^2) = 8 and ln(x^2) + ln(y) = 6.

Solution

We are tasked with solving the following system of equations simultaneously:

  1. lnx+lny2=8\ln x + \ln y^2 = 8
  2. lnx2+lny=6\ln x^2 + \ln y = 6

Step 1: Simplify the logarithmic equations

Using the logarithmic property lna+lnb=ln(ab)\ln a + \ln b = \ln(ab), we can simplify both equations:

First equation:

lnx+lny2=ln(xy2)=8\ln x + \ln y^2 = \ln(xy^2) = 8 So: xy2=e8xy^2 = e^8

Second equation:

lnx2+lny=ln(x2y)=6\ln x^2 + \ln y = \ln(x^2y) = 6 So: x2y=e6x^2y = e^6

We now have the system of equations:

  1. xy2=e8xy^2 = e^8
  2. x2y=e6x^2y = e^6

Step 2: Solve the system of equations

From these equations, we will solve for xx and yy.

From the first equation (xy2=e8xy^2 = e^8):

Solve for xx in terms of yy: x=e8y2x = \frac{e^8}{y^2}

Substitute x=e8y2x = \frac{e^8}{y^2} into the second equation (x2y=e6x^2y = e^6):

(e8y2)2y=e6\left(\frac{e^8}{y^2}\right)^2 y = e^6 Simplify: e16y4y=e6\frac{e^{16}}{y^4} \cdot y = e^6 e16yy4=e6\frac{e^{16}y}{y^4} = e^6 e16y3=e6\frac{e^{16}}{y^3} = e^6

Solve for y3y^3:

y3=e16e6=e10y^3 = \frac{e^{16}}{e^6} = e^{10} y=e103y = e^{\frac{10}{3}}


Step 3: Solve for xx:

Substitute y=e103y = e^{\frac{10}{3}} into x=e8y2x = \frac{e^8}{y^2}: x=e8(e103)2x = \frac{e^8}{(e^{\frac{10}{3}})^2} x=e8e203x = \frac{e^8}{e^{\frac{20}{3}}} x=e8203=e243203=e43x = e^{8 - \frac{20}{3}} = e^{\frac{24}{3} - \frac{20}{3}} = e^{\frac{4}{3}}


Final Answer:

x=e43,y=e103x = e^{\frac{4}{3}}, \quad y = e^{\frac{10}{3}}

Let me know if you'd like further explanation or details! Here are five related questions:

  1. How do logarithmic properties help simplify systems of equations?
  2. How can this approach be extended to equations with more variables?
  3. What are some practical applications of solving exponential systems like this one?
  4. Can the solution be rewritten in decimal form, and why might that be useful?
  5. What are some alternative methods to solve such systems (e.g., substitution or elimination)?

Tip: Always simplify logarithmic equations using properties like lna+lnb=ln(ab)\ln a + \ln b = \ln(ab) or ln(an)=nlna\ln(a^n) = n\ln a to make the problem more manageable.

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Math Problem Analysis

Mathematical Concepts

Logarithmic Equations
Exponential Systems
Simultaneous Equations

Formulas

ln(a) + ln(b) = ln(ab)
ln(a^n) = n * ln(a)
If ln(a) = b, then a = e^b

Theorems

Properties of Logarithms
Laws of Exponents

Suitable Grade Level

Grade 10-12 (Advanced Algebra/Pre-Calculus)