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Solve the following inequality.
I need help with this question.
1 + log₂x - 2 (1/log₂x) > 0
Use the substitution u = log₂x ,
1 + u - 2/u > 0
u/u + u²/u - 2/u > 0
(u + u² - 2) / u > 0
(u + 2)(u - 1) / u > 0
Check for values of u to the left and right of -2 and 1 and see if they satisfy > 0 .
Note that u ≠ 0 as the denominator cannot be 0, i.e division by zero is undefined.
Result :
-2 < u < 0 or u > 1
Substitute back,
-2 < log₂x < 0 or log₂x > 1
Take log on the integers,
-2log₂2 < log₂x < 0(log₂2) or log₂x > log₂2
log₂2⁻² < log₂x < log₂2⁰ or log₂x > log₂2
2⁻² < x < 2⁰ or x > 2
¼ < x < 1 or x > 2