Easy -1.8 This is a straightforward arithmetic sequence question requiring only basic recall: identify the common difference, write out two terms (8 and 11), then apply the standard sum formula S_n = n/2(2a + (n-1)d). All steps are routine with no problem-solving or conceptual challenge beyond direct formula application.
Find the second and third terms in the sequence given by
$$u_1 = 5,$$
$$u_{n+1} = u_n + 3.$$
Find also the sum of the first 50 terms of this sequence. [4]
Question 6:
6 | (5), 8, 11, (14),…isw
a = 5 and d = 3 soi
50
S = (2×5 + (50 – 1) × 3) oe
50
2
3925 | B1
B1
M1
A1
[4] | if M0, SC1 for use of a = 8 and obtaining
4075 | if M0, award B2 if 3925 is obtained
from summing individual terms or if
unsupported
Find the second and third terms in the sequence given by
$$u_1 = 5,$$
$$u_{n+1} = u_n + 3.$$
Find also the sum of the first 50 terms of this sequence. [4]
\hfill \mbox{\textit{OCR MEI C2 Q6 [4]}}