Mathematics
Sequences and Series
Previous Years Questions

## Numerical

Let $$l_{1}, l_{2}, \ldots, l_{100}$$ be consecutive terms of an arithmetic progression with common difference $$d_{1}$$, and let $$w_{1}, w_{2}, \ldo... Let m be the minimum possible value of$${\log _3}({3^{{y_1}}} + {3^{{y_2}}} + {3^{{y_3}}})$$, where$${y_1},{y_2},{y_3}$$are real numbers for which ... Let a1, a2, a3, .... be a sequence of positive integers in arithmetic progression with common difference 2. Also, let b1, b2, b3, .... be a sequence o... Let AP(a; d) denote the set of all the terms of an infinite arithmetic progression with first term a and common difference d > 0. If$$AP(1;3) \cap...
Let X be the set consisting of the first 2018 terms of the arithmetic progression 1, 6, 11, ...., and Y be the set consisting of the first 2018 terms ...
The sides of a right angled triangle are in arithmetic progression. If the triangle has area 24, then what is the length of its smallest side?
Suppose that all the terms of an arithmetic progression (A.P) are natural numbers. If the ratio of the sum of the first seven terms to the sum of the ...
The coefficient of $${x^9}$$ in the expansion of (1 + x) (1 + $${x^2)}$$ (1 + $${x^3}$$) ....$$(1 + {x^{100}})$$ is
Let a, b, c be positive integers such that $${b \over a}$$ is an integer. If a, b, c are in geometric progression and the arithmetic mean of a, b, c i...
A pack contains n cards numbered from 1 to n. Two consecutive numbered cards are removed from the pack and the sum of the numbers on the remaining car...
A pack contains $$n$$ cards numbered from $$1$$ to $$n.$$ Two consecutive numbered cards are removed from the pack and the sum of the numbers on the r...
Let $${{a_1}}$$, $${{a_2}}$$, $${{a_3}}$$........ $${{a_{100}}}$$ be an arithmetic progression with $${{a_1}}$$ = 3 and $${S_p} = \sum\limits_{i = 1}^... Let$${S_k}$$= 1, 2,....., 100, denote the sum of the infinite geometric series whose first term is$$\,{{k - 1} \over {k\,!}}$$and the common ratio ... Let$${a_1},\,{a_{2\,}},\,{a_3}$$......,$${a_{11}}$$be real numbers satisfying$${a_1} = 15,27 - 2{a_2} > 0\,\,and\,\,{a_k} = 2{a_{k - 1}} - {a_{k...
If $${\log _3}\,2\,,\,\,{\log _3}\,({2^x} - 5)\,,\,and\,\,{\log _3}\,\left( {{2^x} - {7 \over 2}} \right)$$ are in arithmetic progression, determine t...

## MCQ (More than One Correct Answer)

Let $$a_{1}, a_{2}, a_{3}, \ldots$$ be an arithmetic progression with $$a_{1}=7$$ and common difference 8. Let $$T_{1}, T_{2}, T_{3}, \ldots$$ be such...
Let $${S_n} = {\sum\limits_{k = 1}^{4n} {\left( { - 1} \right)} ^{{{k\left( {k + 1} \right)} \over 2}}}{k^2}.$$ Then $${S_n}$$can take value(s)
Let $${S_n} = \sum\limits_{k = 1}^n {{n \over {{n^2} + kn + {k^2}}}}$$ and $${T_n} = \sum\limits_{k = 0}^{n - 1} {{n \over {{n^2} + kn + {k^2}}}}$$ ...
A straight line through the vertex p of a triangle PQR intersects the side QR at the point S and the circumcircle of the triangle PQR at the point T. ...
For a positive integer $$n$$, let $$a\left( n \right) = 1 + {1 \over 2} + {1 \over 3} + {1 \over 4} + .....\,{1 \over {\left( {{2^n}} \right) - 1}}$$...
For $$0 < \phi < \pi /2,$$ if $$x =$$$$\sum\limits_{n = 0}^\infty {{{\cos }^{2n}}\phi ,y = \sum\limits_{n = 0}^\infty {{{\sin }^{2n}}\phi ,... If the first and the$$(2n-1)$$st terms of an A.P., a G.P. and an H.P. are equal and their$$n$$-th terms are$$a,b$$and$$c$$respectively, then ## MCQ (Single Correct Answer) Let bi > 1 for I = 1, 2, ......, 101. Suppose logeb1, logeb2, ......., logeb101 are in Arithmetic Progression (A.P.) with the common difference loge2.... Let$${a_1},{a_2},{a_3},.....$$be in harmonic progression with$${a_1} = 5$$and$${a_{20}} = 25.$$The least positive integer$$n$$for which$${a_n...
In the sum of first $$n$$ terms of an A.P. is $$c{n^2 }$$, then the sum of squares of these $$n$$ terms is
Suppose four distinct positive numbers $${a_1},\,{a_{2\,}},\,{a_3},\,{a_4}\,$$ are in G.P. Let $${b_1} = {a_1},{b_2} = {b_1} + {a_2},\,{b_3} = {b_2} +... Let$$\,{V_r}$$denote the sum of first r terms of an arithmetic progression (A.P.) whose first term is r and the common difference is (2r-1). Let$${...
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 $${... Let$${A_1}$$,$${G_1}$$,$${H_1}$$denote the arithmetic, geometric and harmonic means, respectively, of two distinct positive numbers. For$$n \ge 2...
Let $${A_1}$$, $${G_1}$$, $${H_1}$$ denote the arithmetic, geometric and harmonic means, respectively, of two distinct positive numbers. For $$n \ge 2... Let$$\,{V_r}$$denote the sum of first r terms of an arithmetic progression (A.P.) whose first term is r and the common difference is (2r-1). Let$${...
Let $${A_1}$$, $${G_1}$$, $${H_1}$$ denote the arithmetic, geometric and harmonic means, respectively, of two distinct positive numbers. For $$n \ge 2... In the quadratic equation$$\,\,a{x^2} + bx + c = 0,\Delta  = {b^2} - 4ac$$and$$\alpha + \beta ,\,{\alpha ^2} + {\beta ^2},\,{\alpha ^3} ...
An infinite G.P. has first term '$$x$$' and sum '$$5$$', then $$x$$ belongs to
Suppose $$a, b, c$$ are in A.P. and $${a^2},{b^2},{c^2}$$ are in G.P. If $$a < b < c$$ and $$a + b + c = {3 \over 2},$$ then the value of $$a$$ ...
Let $$\alpha$$, $$\beta$$ be the roots of $${x^2} - x + p = 0$$ and $$\gamma ,\delta$$ be the roots of $${x^2} - 4x + q = 0.$$ If $$\alpha ,\beta ,... If the sum of the first$$2n$$terms of the A.P.$$2,5,8,......,$$is equal to the sum of the first$$n$$terms of the A.P.$$57,59,61,.....,$$then$$n...
Let the positive numbers $$a,b,c,d$$ be in A.P. Then $$abc,$$ $$abd,$$ $$acd,$$ $$bcd,$$ are
Consider an infinite geometric series with first term a and common ratio $$r$$. If its sum is 4 and the second term is 3/4, then
The harmonic mean of the roots of the equation $$\left( {5 + \sqrt 2 } \right){x^2} - \left( {4 + \sqrt 5 } \right)x + 8 + 2\sqrt 5 = 0$$ is
Let $${a_1},{a_2},......{a_{10}}$$ be in $$A,\,P,$$ and $${h_1},{h_2},......{h_{10}}$$ be in H.P. If $${a_1} = {h_1} = 2$$ and $${a_{10}} = {h_{10}} =... Let$$n$$be an odd integer. If$$\sin n\theta = \sum\limits_{r = 0}^n {{b_r}{{\sin }^r}\theta ,} $$for every value of$$\theta ,$$then Let$${T_r}$$be the$${r^{th}}$$term of an A.P., for$$r=1, 2, 3, ....$$If for some positive integers$$m$$,$$n$$we have$${T_m} = {1 \over n}$$... If$$x > 1,y > 1,z > 1$$are in G.P., then$${1 \over {1 + In\,x}},{1 \over {1 + In\,y}},{1 \over {1 + In\,z}}$$are in If$$In\left( {a + c} \right),In\left( {a - c} \right),In\left( {a - 2b + c} \right)$$are in A.P., then The number$${\log _2}\,7$$is Sum of the first n terms of the series$${1 \over 2} + {3 \over 4} + {7 \over 8} + {{15} \over {16}} + ............$$is equal to If$$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},\,...
The rational number, which equals the number $$2\overline {357}$$ with recurring decimal is
The third term of a geometric progression is 4. The product of the first five terms is
If $$x,\,y$$ and $$z$$ are $$pth$$, $$qth$$ and $$rth$$ terms respectively of an A.P. and also of a G.P., then $${x^{y - z}}\,{y^{z - x}}\,{z^{x - y}}... ## Subjective If$${a_n} = {3 \over 4} - {\left( {{3 \over 4}} \right)^2} + {\left( {{3 \over 4}} \right)^3} + ....{( - 1)^{n - 1}}{\left( {{3 \over 4}} \right)^n}\...
If a, b, c are in A.P., $${a^2}$$, $${b^2}$$, $${c^2}$$ are in H.P., then prove that either a = b = c or a, b, $${ - {c \over 2}}$$ form a G.P.
Let a, b be positive real numbers. If a, $${{A_1},{A_2}}$$, b are in arithmetic progression, a, $${{G_1},{G_2}}$$, b are in geometric progression and...
Let $${a_1}$$, $${a_2}$$,.....,$${a_n}$$ be positive real numbers in geometric progression. For each n, let $${A_n}$$, $${G_n}$$, $${H_n}$$ be respect...
The fourth power of the common difference of an arithmatic progression with integer entries is added to the product of any four consecutive terms of i...
Let a, b, c, d be real numbers in G.P. If u, v, w, satisfy the system of equations u + 2v + 3w = 6 4u + 5v + 6w = 12 6u + 9v = 4 then show that t...
The real numbers $${x_1}$$, $${x_2}$$, $${x_3}$$ satisfying the equation $${x^3} - {x^2} + \beta x + \gamma = 0$$ are in AP. Find the intervals in wh...
Let p be the first of the n arithmetic means between two numbers and q the first of n harmonic means between the same numbers. Show that q does not li...
If $${S_1}$$, $${S_2}$$, $${S_3}$$,.............,$${S_n}$$ are the sums of infinite geometric series whose first terms are 1, 2, 3, .....................
Solve for x the following equation: $${\log _{(2x + 3)}}(6{x^2} + 23x + 21) = 4 - {\log _{(3x + 7)}}(4{x^2} + 12x + 9)\,$$
Find the sum of the series : $$\sum\limits_{r = 0}^n {{{\left( { - 1} \right)}^r}\,{}^n{C_r}\left[ {{1 \over {{2^r}}} + {{{3^r}} \over {{2^{2r}}}} + ... If$$a > 0,\,b > 0$$and$$\,c > 0,$$prove that$$\,c > 0,$$prove that$$\left( {a + b + c} \right)\left( {{1 \over a} + {1 \over b} + {...
If $$n$$ is a natural number such that $$n = {p_1}{}^{{\alpha _1}}{p_2}{}^{{\alpha _2}}.{p_3}{}^{{\alpha _3}}........{p_k}{}^{{\alpha _k}}$$ and $${p... Find three numbers$$a,b,c$$between$$2$$and$$18$$such that (i) their sum is$$25$$(ii) the numbers$$2,a, b$$are consecutive terms of an ... Does there exist a geometric progression containing$$27, 8$$and$$12$$as three of its terms? If it exits, how many such progressions are possible ?... The interior angles of a polygon are in arithmetic progression. The smallest angle is$${120^ \circ }$$, and the common difference is$${5^ \circ }$$,... The harmonic mean of two numbers is 4.Their arithmetic mean$$A$$and the geometric mean$$G$$satisfy the relation.$$2A + {G^2} = 27$$## Fill in the Blanks Let$$p$$and$$q$$be roots of the equation$${x^2} - 2x + A = 0$$and let$$r$$and$$s$$be the roots of the equation$${x^2} - 18x + B = 0.$$If ... For any odd integer$$n \ge 1,\,\,{n^3} - {\left( {n - 1} \right)^3} + .... + {\left( { - 1} \right)^{n - 1}}\,{1^3} = ........$$Let the harmonic mean and geometric mean of two positive numbers be the ratio 4 : 5. Then the two number are in the ratio ......... The sum of the first n terms of the series$${1^2} + {2.2^2} + {3^2} + {2.4^2} + {5^2} + {2.6^2} + .........$$is$$n\,\,{\left( {n + 1} \right)^2}/2...
The solution of the equation $$lo{g_7}$$ $$lo{g_5}$$ $$\left( {\sqrt {x + 5} + \sqrt x } \right) = 0$$ is .............
The sum of integers from 1 to 100 that are divisible by 2 or 5 is ............
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