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4.1 Expanding (1 + x)^n

Question 5

Given that $k$ is a constant and the binomial expansion of

\sqrt{1 + kx}, \quad |kx| < 1

in ascending powers of $x$ up to the term in $x^3$ is

\frac{1}{4}x + Ax^2 + Bx^3

(i) find the value of $k$ ,

(ii) find the value of the constant $A$ and the constant $B$ .

[5]

Use the expansion to find an approximate value to $1.2\sqrt{1.2}$ .

Show your working and give your answer to 6 decimal places.

[4]

Markscheme

4.1 Expanding (1 + x)^n Questions

A Level
Maths
4.1 Expanding (1 + x)^n

12 exam-style questions on Edexcel A Level Maths 4.1 Expanding (1 + x)^n. Each one has a worked solution and a mark scheme showing where the marks go.

4.1 Expanding (1 + x)^n

Question bank

4.1 Expanding (1 + x)^n

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Question 5

Given that $k$ is a constant and the binomial expansion of

\sqrt{1 + kx}, \quad |kx| < 1

in ascending powers of $x$ up to the term in $x^3$ is

\frac{1}{4}x + Ax^2 + Bx^3

(i) find the value of $k$ ,

(ii) find the value of the constant $A$ and the constant $B$ .

[5]

Use the expansion to find an approximate value to $1.2\sqrt{1.2}$ .

Show your working and give your answer to 6 decimal places.

[4]

Markscheme

4.1 Expanding (1 + x)^n Questions

A Level
Maths
4.1 Expanding (1 + x)^n

12 exam-style questions on Edexcel A Level Maths 4.1 Expanding (1 + x)^n. Each one has a worked solution and a mark scheme showing where the marks go.