Arithmetic Sequence Calculator

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. a()= a()= a()= Common difference d= Sum of the first terms S()= Sum of the first terms S()= Sum of the first terms S()= If the calculator did not compute something or you have identified an error, or you have a suggestion/feedback, please write it in the comments below. Solution Your input: find $$a_{7}$$$, the sum of the first $$15$$$terms, given $$a_{1}=5$$$, the common difference $$d=2$$$. We have that $$a_{1}=5$$$.

We have that $$d=2$$$. Finally, $$a_{7}=a_1+d\left(7 - 1\right)=5+\left(2\right)\left(7 - 1\right)=17$$$.

$$S_{15}=\frac{2a_1+d\left(15 - 1\right)}{2}{15}=\frac{2\left(5\right)+\left(2\right)\left(15 - 1\right)}{2}{15}=285$$$. Answer $$a_{1}=5$$$.

$$a_{7}=17$$$. The common difference is $$d=2$$$.

$$S\left(15\right)=285$$\$.