Binomial expansion

WMA14Topic 4.42 questions

Binomial expansion of $(a + bx)^n$ for any rational $n$ and its range of validity.

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Original practice questions written in the style of the exam.

2 (1 - \frac{x}{4})^{\frac{1}{2}}

B1 Valid for

|x| < 4

(1)

M1 Correct binomial structure, e.g.

\dfrac{\frac{1}{2}\left(-\frac{1}{2}\right)}{2!}\left(-\dfrac{x}{4}\right)^2

(1)

A1

2 - \dfrac{x}{4}

(1)

A1

-\dfrac{x^2}{64} - \dfrac{x^3}{512}

(1)

A1

\sqrt{3.9} \approx 1.974842

(1)