anonymous
  • anonymous
. Find the sum of the given arithmetic series. The sequence whose general term is an=3n represents the positive multiples of 3. Find the sum of the first 102 positive multiples of 3.
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
chestercat
  • chestercat
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
anonymous
  • anonymous
Sum = (n/2)( 2a +(n-1)d )
anonymous
  • anonymous
just about remembering formulas
anonymous
  • anonymous
I dont even need to know what d is ( I could get it by simultaneously eqns ) , because remember that general Tn ( or in your case "an" ) = a +(n-1)d

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

anonymous
  • anonymous
so the part inside the bracket is: a+ ( a+(n-1)d )
anonymous
  • anonymous
ok
anonymous
  • anonymous
now I will call "an" T(n) , ie T(n) = 3n so our sum becomes: Sum = (n/2) ( a +T(n) )
anonymous
  • anonymous
Now n= 102 ( because we want first 102 terms ) and T(n) = 3n ( thats given to us )
anonymous
  • anonymous
so sum = (n/2) ( a+ 3n ) now we just need to know what "a" is , we already know "n" from before ( its 102 ) so if we sub n=1 into our T(n) formula that will give us the first term ( which is "a" ) so T(1) = a = 3(1) = 3
anonymous
  • anonymous
now sub it in sum = (102/2) ( 3 + 3(102) ) = 51 ( 309) = 15759
anonymous
  • anonymous
wow i dont know how this comes so easy for u, thank you. i have like 3 more problems ;(

Looking for something else?

Not the answer you are looking for? Search for more explanations.