Arithmetic Sequence Calculator
Solve arithmetic progressions step by step
The calculator will find the terms, common difference and sum of the first $$$n$$$ terms of the arithmetic sequence from the given data, with steps shown.
Related calculator: Geometric Sequence Calculator
Your Input
Find $$$a_{7}$$$, $$$S_{15}$$$, given $$$a_{1} = 5$$$, $$$d = 2$$$.
Solution
We have that $$$a_{1} = 5$$$.
We have that $$$d = 2$$$.
$$$a_{7} = a_{1} + d \left(7 - 1\right) = 5 + 2 \left(7 - 1\right) = 17$$$
$$$S_{15} = \frac{2 a_{1} + d \left(15 - 1\right)}{2} \cdot 15 = \frac{\left(2\right)\cdot \left(5\right) + 2 \left(15 - 1\right)}{2} \cdot 15 = 285$$$
Answer
$$$a_{7} = 17$$$A
$$$S_{15} = 285$$$A