formula pentru termenul general:
[tex]a_n=a_1+(n-1)r[/tex]
[tex]a_2=a_1+(2-1)r=6+8=14\\a_3=a_1+(3-1)r=6+2\cdot8=6+16=22\\a_{10}=a_1+(10-1)r=6+9\cdot8=6+72=78[/tex]
Formula generala pentru suma:
[tex]S_n=n\cdot\dfrac{a_1+a_n}{2}[/tex]
[tex]S_{10}=10\cdot\dfrac{a_1+a_{10}}{2}=10\cdot\dfrac{6+78}{2}=10\cdot\dfrac{84}{2}=10\cdot42=420[/tex]
