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Consider the sequence S=7+13+21+31+".......

Consider the sequence `S=7+13+21+31+".....+"T_(n)` , find the value of `T_(70)`.

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`S=7+13+21+31+".....+"T_(n)`
`(S=ul " " ul7+ul13+ul21ul+".....+"ulT_(n-1)+ulT_(n))/(0=7+6+8+10+".....+" " n terms "-T_(n))`
`T_(n)=7+6+8+10+".....+"" n terms "`
`T_(n)=7+{6+8+10+".....+"" (n-1) terms "}`
`T_(n)=7+((n-1))/(2) (12+(n-2)2)`
`T_(n)=7+((n-1))/(2)(8+2n)`
`T_(n)=7+(n-1)(4+n)`
`T_(70)=7+69xx74=7+5106=5113`.
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ARIHANT MATHS-SEQUENCES AND SERIES-Exercise (Subjective Type Questions)
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