Show that
∑r=112(3r+7+2r)=8508\sum_{r=1}^{12} \left(3r + 7 + 2^r\right) = 8508∑r=112(3r+7+2r)=8508
A sequence u1,u2,u3,… u_1, u_2, u_3, \dots\,u1,u2,u3,… is defined by
u1=25\displaystyle u_1 = \frac{2}{5}u1=52, un+1=1un\displaystyle u_{n+1} = \frac{1}{u_n}un+1=un1
Find the exact value of ∑r=1100ur\sum_{r=1}^{100} u_r∑r=1100ur.
200 exam-style questions on CCEA A Level Maths 3.3 Sequences and series (A-level only), covering 3.3.1 Sequences and series (A-level only), 3.3.2 Sequences and series (A-level only), 3.3.3 Sequences and series (A-level only), 3.3.4 Sequences and series (A-level only), 3.3.5 Sequences and series (A-level only), 3.3.6 Sequences and series (A-level only), 3.3.7 Sequences and series (A-level only), and 3.3.8 Sequences and series (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.