Week 1. My Arithmetic Sequence and Series

tristenh2015 February 4, 2018 Math 11 No Comments

Arithmetic Sequence: 11, 7, 3, -1, -5

Find $t_{50}$

$t_{n} = t_{1}-(n-1)d$

$t_{50} = 11-(50-1)(-4)$

$t_{50} = 11-(49)(-4)$

$t_{50} = 11-(-196)$

$t_{50} = -207$

Find $S_{50}$

$S_{n}=\frac {n}{2} (t_{1} + t_{n})$

$S_{50}=\frac {50}{2} (11+ (-207))$

$S_{50}=\frac {50}{2} (-196)$

$S_{50}=25 (-196)$

$S_{50}=4,900$

Week 1. My Arithmetic Sequence and Series

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