Hard Logarithm — Problems With Solutions Pdf

Expand: (a\ln 2 + 2(\ln 2)^2 = a^2 + a\ln 2).

Inequality: (\log_{0.2} Y >0). Since base 0.2<1, inequality reverses when exponentiating: (0 < Y < 1) (and (Y>0) already). So (0 < \log_2 (x^2-5x+7) < 1).

Test simple integer (x=2): LHS = (\log_2(7) + \log_3(4) \approx 2.807 + 1.261 = 4.068 > 2) — not working, maybe no simple? Try (x=3): (\log_3(9)=2), (\log_4(5)\approx 1.16), sum=3.16>2. (x) large → each term ~1, sum ~2. Try (x=5): (\log_5(13)\approx 1.593), (\log_6(7)\approx 1.086), sum=2.679. Not 2.

Answer: No real solution. Domain: (x>0, x\neq 1, 2x>0, 2x\neq 1, 4x>0, 4x\neq 1) → (x>0, x\neq 1, x\neq 0.5, x\neq 0.25). hard logarithm problems with solutions pdf

(0 < \log_2 A < 1 \Rightarrow 1 < A < 2 \Rightarrow 1 < x^2-5x+7 < 2).

Cancel (\ln 2) (non‑zero): [ \frac{\ln 2}{\ln x \cdot \ln(2x)} = \frac{1}{\ln(4x)} ] Cross‑multiply: (\ln 2 \cdot \ln(4x) = \ln x \cdot \ln(2x)).

Check domain: all real OK. (x=0, \sqrt{6}, -\sqrt{6}). Solution 3 Domain: (x>0), (x\neq 1), (2x+3>0 \Rightarrow x>-1.5), (x+1>0) and (x+1\neq 1 \Rightarrow x> -1, x\neq 0), plus (x+2>0) (automatic). So (x>0), (x\neq 1). Expand: (a\ln 2 + 2(\ln 2)^2 = a^2 + a\ln 2)

Convert to base 10 (or natural log): Let (\ln x = t). (\log_2 x = \frac{t}{\ln 2}), (\log_3 x = \frac{t}{\ln 3}), (\log_4 x = \frac{t}{\ln 4} = \frac{t}{2\ln 2}).

Title: Hard Logarithm Problems with Detailed Solutions

Equation: (\frac{\ln 2}{\ln x} \cdot \frac{\ln 2}{\ln(2x)} = \frac{\ln 2}{\ln(4x)}). So (0 &lt; \log_2 (x^2-5x+7) &lt; 1)

Let (a = \ln x). Then (\ln(2x) = a + \ln 2), (\ln(4x) = a + 2\ln 2).

Left: (x^2-5x+6>0 \Rightarrow x<2) or (x>3) (same as domain). Right: (x^2-5x+5<0). Roots: (\frac{5\pm\sqrt{5}}{2} \approx 1.38, 3.62). So ( \frac{5-\sqrt{5}}{2} < x < \frac{5+\sqrt{5}}{2}).

Better: Look for (x) such that each term =1: (\frac{\ln(2x+3)}{\ln x}=1 \Rightarrow 2x+3=x \Rightarrow x=-3) impossible. Second term =1: (\ln(x+2)=\ln(x+1) \Rightarrow x+2=x+1 \Rightarrow 2=1) impossible.

Cancel (a\ln 2) both sides: (2(\ln 2)^2 = a^2 \Rightarrow a = \pm \sqrt{2} \ln 2).