HARD
JEE Main
IMPORTANT
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If the sum of the series 20+1935+1915+1845+.......... up to nth  term is 488 and the nth  term is negative, then :

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Important Questions on Sequences and Series

MEDIUM
JEE Main
IMPORTANT
If m arithmetic means (A.Ms) are inserted between 3 and 243 and three geometric means (G.Ms) are inserted between 3 and 243 such that 4th A.M. is equal to 2nd G.M., then m is equal to:
MEDIUM
JEE Main
IMPORTANT
If 1+1-22·1+1-42·3+1-62·5++1-202·19=α-220 β, then an ordered pair α, β is equal to
MEDIUM
JEE Main
IMPORTANT
Let α and β be the roots of x2-3x+p=0 and γ and δ be the roots of x2-6x+q=0. If α,β,γ,δ from a geometric progression. Then ratio (2 q+p):(2 q-p) is
HARD
JEE Main
IMPORTANT
Let a,1a2,,an be a given A.P. whose common difference is an integer and Sn=a1+a2++an. If a1=1,an=300 and 15n50, then the ordered pair Sn-4,an-4 is equal to:
HARD
JEE Main
IMPORTANT
If 210+29·31+28·32++2·39+310=S-211, then S is equal to
MEDIUM
JEE Main
IMPORTANT
If 32sin2α-1,14 and 34-2sin2α are the first three terms of an A.P. for some α , then the sixth term of this A.P. is
HARD
JEE Main
IMPORTANT
If S is the sum of the first 10 terms of the series, tan-113+tan-117+tan-1113+tan-1121+ then tan(S) is equal to :