A community for students. Sign up today!
Here's the question you clicked on:
 0 viewing
 2 years ago
arithmetic sequcences and series
the fourth term is an arithmetic sequcence 6, and the 10th term is 5.
find the common difference and the first term.
how do i go about doing this? i tried so many numbers and the closest thing i got was 1/2 for the common difference :/
 2 years ago
arithmetic sequcences and series the fourth term is an arithmetic sequcence 6, and the 10th term is 5. find the common difference and the first term. how do i go about doing this? i tried so many numbers and the closest thing i got was 1/2 for the common difference :/

This Question is Closed

sirm3d
 2 years ago
Best ResponseYou've already chosen the best response.2try this formula for an arithmetic sequence: \[\large a_na_k=d(nk)\] use n=10, k=4, a10=5 and a4=6 to solve the common difference

satellite73
 2 years ago
Best ResponseYou've already chosen the best response.0terms are \[6,6+d,6+2d,6+3d,6+4d,6+5d,6+6d=5\] solve for \(d\)

sirm3d
 2 years ago
Best ResponseYou've already chosen the best response.2after solving d, use the same formula with n=10, a10=5, k=1 and the value of d to solve a1.

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0okay @sirm3d i got the a10=5 i get 2 and a4=6 i got about 1 1/2

satellite73
 2 years ago
Best ResponseYou've already chosen the best response.0hmm i get \[6+6d=5\] \[6d=11\] \[d=\frac{11}{6}\]

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0wait, what is the formula i should be using? i have this one but i dont know how to use it: avn = av1 + (n  1)d

sirm3d
 2 years ago
Best ResponseYou've already chosen the best response.2you can also use that formula. take n=10 and av10=5 and you'll have two unknowns av1 and d use k=4 and av4=6 and you'll get another equation in av1 and d.

sirm3d
 2 years ago
Best ResponseYou've already chosen the best response.2\[\large n=10: av_{10} =av_1+(101)d\]\[\large n=4: av_{4}=av_1+(41)d\]

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0okay i get... 5= a + 9d and 6= a+3d

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0@sirm3d how can i figure out the rest?

sirm3d
 2 years ago
Best ResponseYou've already chosen the best response.2multiply the second equation by (1) then add it to the first equation. that should eliminate a and leave d to be solved.

sirm3d
 2 years ago
Best ResponseYou've already chosen the best response.2\[\large \begin{matrix}5=a+9d \\ 6=a3d\end{matrix}\]

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0is there anything else to do? i think there is but i dont know what

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0@Outkast3r09 is there anything i gotta do next ? and how?

sirm3d
 2 years ago
Best ResponseYou've already chosen the best response.2now use d = 11/6 in either equation 1 or 2, then solve a \[\huge 5=a+9(\frac{11}{6})\]

sirm3d
 2 years ago
Best ResponseYou've already chosen the best response.2\[\large 5  \frac{33}{2} = a\]

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0dw:1353803493845:dwi end up getting

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0okay, thank you so much i see what i hav to do with fractions. i hate fractions :/
Ask your own question
Ask a QuestionFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.