Solve the Logarithmic Inequality: log₄x × log₅64 ≥ log₅(x³+x²+x+1)

Question

Given 0<X , find X

log4x×log564log5(x3+x2+x+1) \log_4x\times\log_564\ge\log_5(x^3+x^2+x+1)

Video Solution

Solution Steps

00:00 Solve
00:05 We'll use the logarithm product formula, switch between bases
00:17 Let's solve the logarithm and substitute in the exercise
00:47 We'll use the power rule for logarithms, raise the number by the coefficient
00:57 Let's compare the logarithm numbers
01:07 Let's reduce what we can
01:17 We'll use the root formula to find possible solutions
01:22 There is no root less than 0
01:27 Therefore there is no solution to the question

Step-by-Step Solution

To solve this problem, we need to compare the expressions log4x×log564 \log_4 x \times \log_5 64 and log5(x3+x2+x+1)\log_5 (x^3 + x^2 + x + 1).

First, calculate log564 \log_5 64 . We know that 64=43=26 64 = 4^3 = 2^6 . Therefore:
log564=log526log54=6log522log52=3 \log_5 64 = \frac{\log_5 2^6}{\log_5 4} = \frac{6 \log_5 2}{2 \log_5 2} = 3

Next, simplify the left-hand side expression log4x \log_4 x . Using the change of base formula:
log4x=log5xlog54 \log_4 x = \frac{\log_5 x}{\log_5 4}

Therefore, the left-hand side becomes:
log5xlog54×3=3log5x2log52 \frac{\log_5 x}{\log_5 4} \times 3 = \frac{3 \log_5 x}{2 \log_5 2}

For the inequality:
3log5x2log52log5(x3+x2+x+1) \frac{3 \log_5 x}{2 \log_5 2} \ge \log_5 (x^3 + x^2 + x + 1)

We can now equate the right-hand side:
log5x3/2log52log5(x3+x2+x+1) \log_5 x^{3/2\log_5 2} \ge \log_5 (x^3 + x^2 + x + 1)

This implies:
x3/2log52x3+x2+x+1 x^{3/2\log_5 2} \ge x^3 + x^2 + x + 1

Testing and analyzing this expression results in no valid x x satisfying the inequality within real values since exponential growth and polynomial terms do not align. Thus, the inequality cannot be satisfied, and no solution satisfies the given conditions.

Therefore, the solution to the problem is: No solution.

Answer

No solution