Given that ∑r=112(3r+k+2r)=8508\sum_{r=1}^{12} (3r + k + 2^r) = 8508∑r=112(3r+k+2r)=8508, find the value of the constant kkk.
A sequence u1,u2,u3,… u_1, u_2, u_3, \dots\,u1,u2,u3,… is defined by un+1=1un\displaystyle u_{n+1} = \frac{1}{u_n}un+1=un1. Given that ∑r=1100ur=145\sum_{r=1}^{100} u_r=145∑r=1100ur=145, find the possible exact values of u1u_1u1.
326 exam-style questions on Edexcel A Level Maths Sequences and Series, covering 3.1 Arithmetic Sequences, 3.2 Arithmetic Series, 3.3 Geometric Sequences, 3.4 Geometric Series, 3.5 Sum to Infinity, 3.6 Sigma Notation, 3.7 Recurrence Relations, and 3.8 Modelling with Series. Each one has a worked solution and a mark scheme showing where the marks go.