Sequences and series (1 Viewer)

[stressedadfff]

hey can someone explain this to me, im trying to learn myself cos of online school but its currently not working LMAO

like is there a way without physically subbing each term and adding it all or is it just like that

 

[Drongoski]

This sequence is an Arithmetic Sequence:

with 1st term a = and common difference d =

Sum of 1st 20 terms :

Sum of 1st 4 terms :



if my arithmetic is right!

 

[Trebla]

I have moved this to the Maths Advanced forum. For future reference, please post subject specific threads in subject specific forums. Thanks.

 

[stressedadfff]

could anyone explain the following pls

 

[stressedadfff]

This sequence is an Arithmetic Sequence:

with 1st term a = and common difference d =

Sum of 1st 20 terms :

Sum of 1st 4 terms :



if my arithmetic is right!

THANK YOU

 

[Eagle Mum]

If on the first day he lays ‘k’ bricks, second day he lays ‘2k’ bricks for a total of (1+2)k bricks, then by the end of the tenth day, he will have laid the arithmetic sum of the first ten integers multiplied by k:

(1+2+3+4+5+6+7+8+9+10)k = k(10x11)/2 = 55k
For 55k = 1100, k = 20

For the question, the median is still 12.
The median is the central score when you line up all the scores in either increasing or decreasing order. By adding the same number (two) of scores which are less than (4,7) and greater than (13,14) the median (12), the median value doesn’t change.

 

[stressedadfff]

thanks!