Math Problem Statement

solve

√log p + √log q + log √p + log √q = 67. √log p, √log q, log √p and log √q are all positive integers. What is the maximum value of log10 pq?

Solution

The problem appears to ask for the maximum value of log10pq\log_{10} pq given the following equation and conditions:

logp+logq+logp+logq=67\sqrt{\log p} + \sqrt{\log q} + \log \sqrt{p} + \log \sqrt{q} = 67 and that logp,logq,logp,logq\sqrt{\log p}, \sqrt{\log q}, \log \sqrt{p}, \log \sqrt{q} are all positive integers.

Step 1: Simplify the equation

We can begin by simplifying the given equation. First, recall that: logp=12logpandlogq=12logq\log \sqrt{p} = \frac{1}{2} \log p \quad \text{and} \quad \log \sqrt{q} = \frac{1}{2} \log q Thus, the equation becomes: logp+logq+12logp+12logq=67\sqrt{\log p} + \sqrt{\log q} + \frac{1}{2} \log p + \frac{1}{2} \log q = 67

Step 2: Assign variables to simplify further

Let x=logpx = \sqrt{\log p} and y=logqy = \sqrt{\log q}. This implies: logp=x2andlogq=y2\log p = x^2 \quad \text{and} \quad \log q = y^2 Substituting these into the equation, we get: x+y+12x2+12y2=67x + y + \frac{1}{2} x^2 + \frac{1}{2} y^2 = 67 Multiply the entire equation by 2 to eliminate the fractions: 2x+2y+x2+y2=1342x + 2y + x^2 + y^2 = 134 Rearrange this as: x2+2x+y2+2y=134x^2 + 2x + y^2 + 2y = 134 This can be factored as: (x+1)2+(y+1)2=136(x+1)^2 + (y+1)^2 = 136

Step 3: Solve for integer solutions

Now, we need to find integer values of xx and yy such that the sum of squares equals 136. Let's check pairs of integers whose squares sum to 136:

13612=135(no solution for the remaining term)136 - 1^2 = 135 \quad (\text{no solution for the remaining term}) 13622=132(no solution for the remaining term)136 - 2^2 = 132 \quad (\text{no solution for the remaining term}) [ 136 - 7^2 = 87 \quad (\text{no solution for the remaining term})

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Math Problem Analysis

Mathematical Concepts

Logarithms
Algebra
Quadratic Equations

Formulas

log √p = (1/2) log p
log √q = (1/2) log q
(x + 1)^2 + (y + 1)^2 = 136

Theorems

Logarithmic properties: log(a * b) = log a + log b
Sum of squares: finding integer solutions

Suitable Grade Level

Grades 9-12