Friday

October 24, 2014

October 24, 2014

Posted by **Ellie** on Sunday, October 25, 2009 at 8:45pm.

a_n=

-a_n=a_1+(n-1)d--so a_n=21+(n-1)-8

*a_n=-168-8n

why isnt this right?

- math -
**Quidditch**, Sunday, October 25, 2009 at 9:00pmYou are close. You have an error:

Your step:

a_n = 21 + (n - 1) - 8

should be:

a_n = 21 + (n - 1) * (-8)

- math -
**Ellie**, Sunday, October 25, 2009 at 9:03pmoh yeah sorry i wrote that wrong i put -168-8n but it still said my answer was wrong

- math -
**Quidditch**, Sunday, October 25, 2009 at 9:15pma_n = 21 + (n-1)*(-8)

Expand that using the distributive law.

The first term, 21, is not multiplied by -8. Only the terms in parenthesis are multiplied by -8.

- math -
**Ellie**, Sunday, October 25, 2009 at 9:54pmi figured out what i was doing thank you so much!

- math -
**Quidditch**, Sunday, October 25, 2009 at 10:03pmYou're very welcome.

**Answer this Question**

**Related Questions**

Calculus - If a_n>0 and a_(n+1) <= a_n, does the alternating series ∑...

Calculus - If a_n does not equal zero for any n>=1 and ∑a_n converges ...

Algebra - find the arithmetic mean A_n-1_-3.9, A_n+1_=7.1

Calculus - Find a series ∑a_n for which ∑(a_n)^2 converges but &#...

mathematical statistics - Suppose a_n∈ [0,1] and X_n is a sequence of i.i....

Discrete Math - Solve the recurrence relation a_n = -2a_n-1 + 15a_n-2, n ≥...

Calculus - If a_n >0 and b_n >0 and series ∑ sqrt( (a_n)^2 +(b_n)^2...

Algebra 2 - The sequence is defined by a recursion formula. Write the first four...

Algebra 2 - The sequence is defined by a recursion formula. Write the first four...

Algebra 2 - The sequence is defined by a recursion formula, write the first four...