Question

I’m having trouble with this practice problem in pre calculus.

Answer 1

Given the sequence:

`11+17+23+29+35+41`

This is equivalent to:

`(5+6)+(5+12)+(5+18)+(5+24)+(5+30)+(5+36)`

Or:

`(5+6\cdot1)+(5+6\cdot2)+(5+6\cdot3)+(5+6\cdot4)+(5+6\cdot5)+(5+6\cdot6)`

Now, using "i" as an index, the sum is:

`=\sum ^6_(i\mathop=1)(5+6\cdot i)`