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In a sequence an,a1=2,an+1=1-1an for n1,nN. Let Pn be the product of its first n terms, then the value of P2023 is equal to

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Important Questions on Sequences and Series

MEDIUM
If the product of n positive numbers is unity, then their sum is
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The number of terms common to both the arithmetic progressions 2,5,8,11,,179 and 3,5,7,9,,101 is
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The value of 34+536+7144++175184+198100 is 
HARD
Consider the sequence a1,a2,a3, such that a1=1,a2=2 and an+2=2an+1+an for n=1,2,3,
If a1+1a2a3·a2+1a3a4·a3+1a4a5a30+1a31a32=2αC3161 then α is equal to
MEDIUM
The sum of the following series 1+6+912+22+327+1212+22+32+429+15(12+22++52)11+.... up to 15 terms, is:
HARD
If 1+x-2x26=A0+r=112Arxr, then value of A2+A4+A6++A12 is
EASY

Find the missing (?) in the series- 14, 28, 42, 56, ?, 84, 98 

1. 68
2. 70
3. 72
4. 74

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The sum of the series 1x+1+2x2+1+22x4+1++2100x2100+1 when x=2 is:
MEDIUM
If 0<x<1 and y=12x2+23x3+34x4+, then the value of e1+y at x=12 is:
HARD
n=0n3((2n)!)+(2n-1)(n!)(n!)((2n)!)=ae+be+c where   a, b, c   and  e=n=01n!  Then a2-b+c is  equal to _______
EASY
Select the correct set of symbols: 219137=195
MEDIUM

Let <an> be a sequence such that a1+a2+...+an=n2+3nn+1n+2. If 28k=1101ak=p1 p2 p3 ... pm, where p1, p2, ... pm are the first m prime numbers, then m is equal to

MEDIUM

On simplification the product

x1-y1x2+y2...x10 + y10

How many such terms are there which will have only single x and rest y's ?

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A sequence is given in which one term (or more terms) is missing. From the given options, choose the correct one that can complete the sequence.

1, 6, 15, ?, 45, 66, 91

EASY

Complete the following series each of which follows a certain pattern:

3, 12, 27, 48, 75, 108, _____?

EASY

Find the missing term in the following series: 

2, 3, 4, 6, 8, 12, 16, 24, ?

MEDIUM
A car driver increases the average speed of his car by 3 km/h every hour. The total distance travelled in 7 h if the distance covered in the first hour was 30 km, is:  
MEDIUM
Let 1x1, 1x2,,1xn(xi0 for i=1, 2,., n) be in A.P. such that x1=4 and x21=20 . If n is the least positive integer for which xn>50, then i=1n1xi is equal to