AQA Further AS Paper 1 2018 June — Question 15

Exam BoardAQA
ModuleFurther AS Paper 1 (Further AS Paper 1)
Year2018
SessionJune
TopicSequences and series, recurrence and convergence

15 (b) Use the method of differences to show that $$\sum _ { r = 1 } ^ { n } \frac { 1 } { ( r + 2 ) ( r + 3 ) } = \frac { n } { 3 ( n + 3 ) }$$
\multirow[t]{26}{*}{16}Two matrices \(\mathbf { A }\) and \(\mathbf { B }\) satisfy the equation
Find \(\mathbf { A }\).
Find the exact solution to the equation $$\sinh \theta ( \sinh \theta + \cosh \theta ) = 1$$
18
\(\alpha , \beta\) and \(\gamma\) are the real roots of the cubic equation \(x ^ { 3 } + m x ^ { 2 } + n x + 2 = 0\)
By considering \(( \alpha - \beta ) ^ { 2 } + ( \gamma - \alpha ) ^ { 2 } + ( \beta - \gamma ) ^ { 2 }\), prove that \(m ^ { 2 } \geq 3 n\)