Question

If x is positive and $logx\ge log2+\frac{1}{2}logx$, then:

• A. x has no minimum or maximum value
• B. the maximum value of x is 1
• C. the minimum value of x is 4
• D. the maximum value of x is 4

Answer 1

Answer: (C)

the minimum value of x is 4

$\log x\ge \log 2+\frac{1}{2}\log x,x>0\frac{1}{2}\log x\ge \log 2\log x\ge 2\log 2\therefore x\ge 4$

Minimum value of x is 4.