MMa0InezTrOCatE
MMa0InezTrOCatE MMa0InezTrOCatE
  • 31-07-2016
  • Mathematics
contestada

The first term of an arithmetic sequence is 2 and the fourth term is 11. Find the sum of the first 50 terms.

Respuesta :

dalendrk
dalendrk dalendrk
  • 31-07-2016
[tex]a_1=2;\ a_4=11;\ S_{50}=?\\\\a_4-a_1=3d\\\\subtitute\\\\3d=11-2\\3d=9\ \ \ |divide\ both\ sides\ by\ 3\\d=3\\\\S_n=\dfrac{[2a_1+(n-1)d]\cdot n}{2}\\\\subtitute\\\\S_{50}=\dfrac{(2\cdot2+(50-1)\cdot3)\cdot50}{2}=(4+49\cdot3)\cdot25=(4+147)\cdot25\\\\=151\cdot25=3,775\\\\Answer:\boxed{S_{50}=3,775}[/tex]
Answer Link

Otras preguntas

A 15% tip represents the ratio 15 cents to 100 cents. Why does this make 15% a unit-less factor?
DVDS are on sale for $24 each. Which expression can be used to find the cost in dollars of buying 4 DVDS.
Write and evaluate expression for 21+18+16+18 in addition then in addition and multiplication
Each side of an equilateral triangle measures 9cm. Find the height, h, of the triangle.
Evaluate 5a+3b and (5+a)(3+b) For a =2 and b=4. How Is the order Of the steps different For the two expressions?
what conditions allow dead organisms to change into fossils
calculate the tax levied on property based on assued value.round to the nearest hundredth. $75,000 market value 80% assessed value $1.7
7,000 is 10 times as much as
g is proportional to the square of t. If t=2 and g=64, find g when t=3.5.
80 is 40% of what number?