Find the first three terms of the expansion of (9+2x)−12\displaystyle (9 + 2x)^{-\frac{1}{2}}(9+2x)−21 in ascending powers of xxx, giving each coefficient in its simplest form.
The expansion of
a+bx9+2x\displaystyle \frac{a + bx}{\sqrt{9 + 2x}}9+2xa+bx
in ascending powers of x x\,x begins 3+x+…3 + x + \dots3+x+…
Find the value of a a\,a and the value of bbb.
231 exam-style questions on WJEC A Level Maths 3.4 Sequences and Series (A-level only), covering 3.4.1 Sequences and Series (A-level only), 3.4.2 Sequences and Series (A-level only), 3.4.3 Sequences and Series (A-level only), 3.4.4 Sequences and Series (A-level only), 3.4.5 Sequences and Series (A-level only), 3.4.6 Sequences and Series (A-level only), and 3.4.7 Sequences and Series (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.