Question
The maximum number of non-negative real roots of 2x– x – 1 = 0 equals
(CAT 2003)
(CAT 2003)
Answer: Option B
:
B
Option (b) It is clear that the equation 2x - x - 1 = 0 is satisfied by x = 0 and 1 only. For x > 1, f(x) = 2x – x – 1 starts increasing.
Alternately
Draw the graph of
y=x+1
y=2x
for x<0 there is only one root.
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:
B
Option (b) It is clear that the equation 2x - x - 1 = 0 is satisfied by x = 0 and 1 only. For x > 1, f(x) = 2x – x – 1 starts increasing.
Alternately
Draw the graph of
y=x+1
y=2x
for x<0 there is only one root.
Was this answer helpful ?
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