We are given the equations:
(12)k=3\left(\frac{1}{2}\right)^k = \sqrt{3}(13)m=2\left(\frac{1}{3}\right)^m = \sqrt{2}
We need to determine the value of mk2\frac{mk}{2}.
Step 1: Express in Logarithmic Form
Taking the natural logarithm (ln) on both sides:
kln(12)=ln(3)k \ln\left(\frac{1}{2}\right) = \ln(\sqrt{3})mln(13)=ln(2)m \ln\left(\frac{1}{3}\right) = \ln(\sqrt{2})
Using logarithm properties:
ln(12)=−ln2,ln(13)=−ln3\ln\left(\frac{1}{2}\right) = -\ln 2, \quad \ln\left(\frac{1}{3}\right) = -\ln 3ln(3)=12ln3,ln(2)=12ln2\ln(\sqrt{3}) = \frac{1}{2} \ln 3, \quad \ln(\sqrt{2}) = \frac{1}{2} \ln 2
Thus, the equations simplify to:
−kln2=12ln3- k \ln 2 = \frac{1}{2} \ln 3−mln3=12ln2- m \ln 3 = \frac{1}{2} \ln 2
Step 2: Solve for kk and mm
Rearrange the equations:
k=−12ln3ln2=12ln3ln2k = -\frac{\frac{1}{2} \ln 3}{\ln 2} = \frac{1}{2} \frac{\ln 3}{\ln 2}m=−12ln2ln3=12ln2ln3m = -\frac{\frac{1}{2} \ln 2}{\ln 3} = \frac{1}{2} \frac{\ln 2}{\ln 3}
Step 3: Compute mk2\frac{mk}{2}
mk2=12×(12ln3ln2×12ln2ln3)\frac{mk}{2} = \frac{1}{2} \times \left(\frac{1}{2} \frac{\ln 3}{\ln 2} \times \frac{1}{2} \frac{\ln 2}{\ln 3} \right)
Since ln3ln2×ln2ln3=1\frac{\ln 3}{\ln 2} \times \frac{\ln 2}{\ln 3} = 1, we get:
mk2=12×14=18\frac{mk}{2} = \frac{1}{2} \times \frac{1}{4} = \frac{1}{8}
Step 4: Select the Correct Answer
Thus, the correct answer is C. 18\frac{1}{8}
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