A vertical farm designs its irrigation system based on the number of seedling trays in each tier. The number of trays in the first three tiers is given by the expressions:
2k+5,4k−2,8k−23 2k + 5, \quad 4k - 2, \quad 8k - 23 2k+5,4k−2,8k−23Show that k=7k = 7k=7 is the only value for which these expressions form an arithmetic sequence.
Write down the number of trays in the first tier.
Determine the common difference of the sequence representing the number of trays per tier.
The total number of trays in the first NNN tiers is denoted by SNS_NSN. Given that
SN<80 000 S_N < 80\,000 SN<80000 SN+1>80 000 S_{N+1} > 80\,000 SN+1>80000find the value of NNN.
308 exam-style questions on OCR (MEI) A Level Maths 1.6 Sequences and Series, covering 1.6.1 Binomial expansion for positive integer n, 1.6.2 Factorial and combinations notation, 1.6.3 Binomial expansion for rational n (A-level only), 1.6.4 Binomial expansion of (a + bx)^n via factoring (A-level only), 1.6.5 Binomial approximating polynomials (A-level only), 1.6.6 What a sequence is; finite and infinite (A-level only), 1.6.7 Generate a sequence by formula or recurrence (A-level only), 1.6.8 A series as a sum of terms (A-level only), 1.6.9 Sigma notation (A-level only), 1.6.10 Increasing, decreasing and periodic sequences (A-level only), 1.6.11 Convergent and divergent sequences (A-level only), 1.6.12 Arithmetic sequences and series (A-level only), 1.6.13 Standard formulae for arithmetic series (A-level only), 1.6.14 Geometric sequences and series (A-level only), 1.6.15 Standard formulae for geometric series (A-level only), 1.6.16 Sum to infinity of a geometric series (A-level only), and 1.6.17 Sequences and series in modelling (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.