The electrical current InI_nIn, measured in milliamperes, flowing through a logic gate is monitored at discrete clock cycles. The sequence of current values is defined by the recurrence relation
I1=0.4andIn+1=12Infor n≥1 I_1 = 0.4 \quad \text{and} \quad I_{n+1} = \frac{1}{2I_n} \quad \text{for } n \ge 1 I1=0.4andIn+1=2In1for n≥1Find the values of I2I_2I2, I3I_3I3 and I4I_4I4.
State the period of the sequence.
Determine the exact value of ∑n=1101In\sum_{n=1}^{101} I_n∑n=1101In.
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.