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Class 11
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Maths
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Mathematics
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Sequences and Series
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Sequences and series
sequences and series
Browse All Exercises
Exercise 9.1
Exercise 9.2
Exercise 9.3
Exercise 9.4
Exercise 9.5
Exercise
Find the sum of all natural numbers lying between
$100$
and
$1000$
, which are multiples of
$5$
.
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>
The sum of
$n$
terms of two arithmetic progressions are in the ratio
$5n+4:9n+6$
. Find the ratio of their
$18_{th}$
terms.
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>
How many terms of the
$A.P$
.
$−6,−211 ,−5,...$
are needed to give the sum
$−25$
?
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>
Find the sum to
$n$
terms of the
$A.P.$
, whose
$k_{th}$
term is
$5k+1$
.
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>
If the sum of
$n$
terms of an
$A.P.$
is
$(pn+qn_{2})$
, where
$p$
and
$q$
are constants, find the common difference.
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>
In an
$A.P$
.,the first term is
$2$
and the sum of the first five terms is one-fourth of the next five terms. Show that
$20_{th}$
term is
$−112$
.
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>
In an A.P., if
$p_{th}$
term is
$q1 $
and
$q_{th}$
term is
$p1 $
, prove that the sum of first
$pq$
terms is
$21 (pq+1)$
, where
$p=q$
.
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>
Find the sum of odd integers from
$1$
to
$2001$
.
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>
If the sum of first
$p$
terms of an A.P.is equal to the sum of the first
$q$
terms, then find the sum of the first
$(p+q)$
terms.
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>
If the sum of a certain number of terms of the A.P.
$25,22,19,...$
is
$116$
. Find the last term.
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>
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