Question

do anyone know how to figure this problem out..

evaluate the series
∑_(k=1)^4▒〖(4k+1)〗

Answer 1

k=[1,4] i assume

Answer 2

what is the upper limit of the sum? what is that big black square?

Answer 3

then its just a matter of summing up the sequence generated by the equation

Answer 4

the ^ tends to mean up

Answer 5

up ^ there, and down_there

Answer 6

@fool for math yes its like that

Answer 7

You want \[ \sum \limits_{k\to 1 }^4 (4k+1) =\] ?

Answer 8

Then the answer is 44

Answer 9

first plus last times number of terms divided by 2

Answer 10

For more rigorous users,

\[ \sum \limits_{k= 1 }^n (4k+1) = 3 n+2 n^2 \]

Answer 11

If you sub explicit def into Gauss formula you don't need last term\[s=\frac{n}{2}(2a _{1}-(n-1)d)\]just fyi

Answer 12

i only got so many brain cells left that fire on all cylindars ;)

Answer 13

i do good just to recall the form much less nuances ;)

Answer 14

@Mandolino:Yes or you could use Arithmetic progressions