A-level · Sequences & series

The binomial expansionExam-style questions

Expanding (a + b)^n with binomial coefficients — Pascal's triangle and nCr — and picking out a single term or coefficient without expanding everything.

9 questions · A-level level · mark scheme and worked solution on each · no sign-up to try

DifficultyAllLevel 2Level 3Level 4
  1. 1
    Find the term which is independent of xx in the expansion of (2x−3x2)6\left(2x - \dfrac{3}{x^{2}}\right)^{6}. (4 marks)
    Level 2 · 4 marksTry it
  2. 2
    Find the coefficient of x3x^3 in the expansion of (2−x)6(2 - x)^6.
    Level 3 · 2 marksTry it
  3. 3
    In the expansion of (3+kx)4(3 + kx)^4, the coefficient of x2x^2 is 216216. Find the possible values of the constant kk.
    Level 3 · 3 marksTry it
  4. 4
    Find the coefficient of x2x^2 in the expansion of (1+x)(2−x)4(1 + x)(2 - x)^4.
    Level 3 · 3 marksTry it
  5. 5
    (a) Find the first four terms in the expansion of (1−2x)7(1 - 2x)^7 in ascending powers of xx.

    (4 marks)

    In the expansion of (1−2y−4y2)7(1 - 2y - 4y^2)^7 in ascending powers of yy, the coefficient of y3y^3 is cc.
    (b) By writing 1−2y−4y21 - 2y - 4y^2 in the form 1−2x1 - 2x, use your answer to part (a) to determine the value of cc.

    (4 marks)
    Level 4 · 8 marksTry it

4 more questions on the binomial expansion

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