1
IIT-JEE 2007
MCQ (Single Correct Answer)
+4
-1
Let $${A_1}$$, $${G_1}$$, $${H_1}$$ denote the arithmetic, geometric and harmonic means, respectively, of two distinct positive numbers. For $$n \ge 2,\,Let\,{A_{n - 1}}\,\,and\,\,{H_{n - 1}}$$ have arithmetic, geometric and harminic means as $${A_n},{G_n}\,,{H_n}$$ repectively.

Which one of the following statements is correct ?

A
$${H_1} > {H_2}\, > {H_3} > ...$$
B
$${H_1} < {H_2}\, < {H_3} < ...$$
C
$${H_1} > {H_2}\, > {H_3} > ...$$ and $${H_1} < {H_2}\, < {H_3} < ...$$
D
$${H_1} < {H_2}\, < {H_3} < ...$$ and $${H_1} > {H_2}\, > {H_3} > ...$$
2
IIT-JEE 2007
MCQ (Single Correct Answer)
+4
-1
Let $$\,{V_r}$$ denote the sum of first r terms of an arithmetic progression (A.P.) whose first term is r and the common difference is (2r-1). Let $${T_r} = \,{V_{r + 1}} - \,{V_r} - 2\,\,\,and\,\,\,{Q_r} = \,{T_{r + 1}} - \,{T_r}\,for\,r = 1,2,...$$

The sum $${V_1}$$+$${V_2}$$ +...+$${V_n}$$ is

A
$${1 \over {12}}n(n + 1)\,(3{n^2} - n + 1)$$
B
$${1 \over {12}}n(n + 1)\,(3{n^2} + n + 2)$$
C
$${1 \over 2}n(2{n^2} - n + 1)$$
D
$${1 \over 3}(2{n^3} - 2n + 3)$$
3
IIT-JEE 2005 Screening
MCQ (Single Correct Answer)
+2
-0.5
In the quadratic equation $$\,\,a{x^2} + bx + c = 0,$$ $$\Delta $$ $$ = {b^2} - 4ac$$ and $$\alpha + \beta ,\,{\alpha ^2} + {\beta ^2},\,{\alpha ^3} + {\beta ^3},$$ are in G.P. where $$\alpha ,\beta $$ are the root of $$\,\,a{x^2} + bx + c = 0,$$ then
A
$$\Delta \ne 0$$
B
$$b\Delta = 0$$
C
$$c\Delta = 0$$
D
$$\Delta = 0$$
4
IIT-JEE 2004 Screening
MCQ (Single Correct Answer)
+2
-0.5
An infinite G.P. has first term '$$x$$' and sum '$$5$$', then $$x$$ belongs to
A
$$x < - 10$$
B
$$ - 10 < x < 0$$
C
$$0 < x < 10$$
D
$$x > 10$$
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