Write an explicit formula for a1 = –2, an = an – 1 + 4, n ≥ 2 a. an = –4n – 6 b. an = –2n – 6 c. an = 4n – 6 d. an = 4n + 6

According to the recursive formula,

and so on, with the general formula

Then

and the answer is C.

C. an = 4n -6

Step-by-step explanation:

Only one of the offered choices gives a1=-2 for n=1.

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The recursive formula tells you ...

a2 -a1 = 4

The only choices that increase by 4 when n increases by 1 are choices C and D. Of these, choice D gives a1=4·1+6 = 10 ≠ -2.

Choice C gives a1 = 4·1 -6 = -2, as required.

A.  

Her test trials had a low level of accuracy but a high level of precision.

 B.  

Her test trials had a high level of accuracy but a low level of precision.

 C.  

Her test trials had a high level of accuracy and a high level of precision.

 D.  

Her test trials had a low level of accuracy and a low level of precision.