OCR H240/02 2019 June — Question 2

Exam BoardOCR
ModuleH240/02 (Pure Mathematics and Statistics)
Year2019
SessionJune
TopicGeneralised Binomial Theorem
TypeExpand and state validity

2
  1. Find the coefficient of \(x ^ { 5 }\) in the expansion of \(( 3 - 2 x ) ^ { 8 }\).
    1. Expand \(( 1 + 3 x ) ^ { 0.5 }\) as far as the term in \(x ^ { 3 }\).
    2. State the range of values of \(x\) for which your expansion is valid. A student suggests the following check to determine whether the expansion obtained in part (b)(i) may be correct.
      "Use the expansion to find an estimate for \(\sqrt { 103 }\), correct to five decimal places, and compare this with the value of \(\sqrt { 103 }\) given by your calculator."
    3. Showing your working, carry out this check on your expansion from part (b)(i).