1
IIT-JEE 1990
MCQ (Single Correct Answer)
+2
-0.5
The number $${\log _2}\,7$$ is
A
an integer
B
a rational number
C
an irrational number
D
a prime number
2
IIT-JEE 1988
MCQ (Single Correct Answer)
+2
-0.5
Sum of the first n terms of the series $${1 \over 2} + {3 \over 4} + {7 \over 8} + {{15} \over {16}} + ............$$ is equal to
A
$${2^n} - n - 1$$
B
$$1 - {2^{ - n}}$$
C
$$n + {2^{ - n}} - 1$$
D
$${2^n} + 1$$
3
IIT-JEE 1985
MCQ (Single Correct Answer)
+2
-0.5
If $$a,\,b,\,c$$ are in GP., then the equations $$\,\,\alpha {x^2} + 2bx + c = 0$$ and $$d{x^2} + 2ex + f = 0$$ have a common root if $${d \over a},\,{e \over b},{f \over c}$$ are in ________.
A
A.P.
B
GP.
C
H.P.
D
none of these
4
IIT-JEE 1983
MCQ (Single Correct Answer)
+1
-0.25
The rational number, which equals the number $$2\overline {357} $$ with recurring decimal is
A
$${{2355} \over {1001}}$$
B
$${{2379} \over {997}}$$
C
$${{2355} \over {999}}$$
D
none of these
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