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4.2 Expanding (a + bx)^n

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Question 92

Determine the first two terms, in ascending powers of $u$ , of the binomial expansion of

\left(1 + \frac{3}{4}u\right)^{-\frac{1}{3}}

[2]

A signal processing engineer models the gain $G\,$ of a circuit at frequency offset $x\,$ using the formula:

\cos(5x) + \left(1 + 6x^2\right)^{-\frac{1}{3}}

Hence, for small values of $x$ , show that the gain can be approximated by

\approx A + Bx + Cx^2

where $A$ , $B\,$ and $C\,$ are constants to be found.

[4]

Markscheme

4.2 Expanding (a + bx)^n Questions

A Level
Maths
4.2 Expanding (a + bx)^n

99 exam-style questions on Edexcel A Level Maths 4.2 Expanding (a + bx)^n. Each one has a worked solution and a mark scheme showing where the marks go.

4.2 Expanding (a + bx)^n

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4.2 Expanding (a + bx)^n

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Question 92

Determine the first two terms, in ascending powers of $u$ , of the binomial expansion of

\left(1 + \frac{3}{4}u\right)^{-\frac{1}{3}}

[2]

A signal processing engineer models the gain $G\,$ of a circuit at frequency offset $x\,$ using the formula:

\cos(5x) + \left(1 + 6x^2\right)^{-\frac{1}{3}}

Hence, for small values of $x$ , show that the gain can be approximated by

\approx A + Bx + Cx^2

where $A$ , $B\,$ and $C\,$ are constants to be found.

[4]

Markscheme

4.2 Expanding (a + bx)^n Questions

A Level
Maths
4.2 Expanding (a + bx)^n

99 exam-style questions on Edexcel A Level Maths 4.2 Expanding (a + bx)^n. Each one has a worked solution and a mark scheme showing where the marks go.