Indices and Surds

325 questions · 17 question types identified

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Rationalize denominator simple

A question is this type if and only if it asks to rationalize a denominator of the form a/(b + c√d) or a/(b - c√d) by multiplying by the conjugate, resulting in the form p + q√r.

79 Easy -1.1
24.3% of questions
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2 Express \(\frac { 3 + \sqrt { 20 } } { 3 + \sqrt { 5 } }\) in the form \(a + b \sqrt { 5 }\).
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Easiest question Easy -1.8 »
5. (a) Write \(\sqrt { 45 }\) in the form \(a \sqrt { 5 }\), where \(a\) is an integer.
(b) Express \(\frac { 2 ( 3 + \sqrt { 5 } ) } { ( 3 - \sqrt { 5 } ) }\) in the form \(b + c \sqrt { 5 }\), where \(b\) and \(c\) are integers.
\section*{6.} \begin{figure}[h]
\captionsetup{labelformat=empty} \caption{Figure 1} \includegraphics[alt={},max width=\textwidth]{815e288c-0140-4c12-9e89-b0bb4fb1a8c1-07_607_844_310_555}
\end{figure} Figure 1 shows a sketch of the curve with equation \(y = \mathrm { f } ( x )\). The curve passes through the points \(( 0,3 )\) and \(( 4,0 )\) and touches the \(x\)-axis at the point \(( 1,0 )\). On separate diagrams sketch the curve with equation
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Hardest question Moderate -0.3 »
3 In this question you must show detailed reasoning.
Find the value of \(k\) such that \(\frac { 1 } { \sqrt { 5 } + \sqrt { 6 } } + \frac { 1 } { \sqrt { 6 } + \sqrt { 7 } } = \frac { k } { \sqrt { 5 } + \sqrt { 7 } }\).
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Evaluate numerical powers

A question is this type if and only if it asks to evaluate a specific numerical expression involving powers or roots with no algebraic variables, such as 16^(1/2), 81^(3/4), or (1/25)^(-1/2).

45 Easy -1.6
13.8% of questions
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Evaluate \(49^{\frac{1}{2}} + 8^{\frac{1}{3}}\). [3]
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Easiest question Easy -2.0 »
State the value of each of the following.
  1. \(2^{-3}\) [1]
  2. \(9^0\) [1]
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Hardest question Standard +0.8 »
2 A civilisation which works in base 5 sends out the first 6 digits of \(\pi\) as 3.032 32. Convert this to base 10.
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Simplify algebraic expressions with indices

A question is this type if and only if it asks to simplify an algebraic expression involving powers, roots, or fractional indices, such as (25x^4)^(1/2) or (2x^(-1/4))^4, typically resulting in the form kx^n.

42 Easy -1.3
12.9% of questions
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Factorise completely \(x - 4 x ^ { 3 }\)
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Easiest question Easy -1.8 »
1 Express as a single power of \(a\) $$\frac { a ^ { 2 } } { \sqrt { a } }$$ where \(a \neq 0\) Circle your answer. \(a ^ { 1 }\) \(a ^ { \frac { 3 } { 2 } }\) \(a ^ { \frac { 5 } { 2 } }\) \(a ^ { 4 }\)
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Hardest question Standard +0.3 »
Given that \(x > 0\) and \(x \neq 25\), fully simplify $$\frac{10 + 5x - 2x^{\frac{1}{2}} - x^{\frac{3}{2}}}{5 - \sqrt{x}}$$ Fully justify your answer. [4 marks]
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Expand and simplify surd expressions

A question is this type if and only if it asks to expand brackets containing surds and simplify, such as (3 + √5)(3 - √5) or (5 - √8)(1 + √2), typically resulting in the form a + b√c.

31 Easy -1.2
9.5% of questions
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Simplify \((3 + \sqrt{5})(3 - \sqrt{5})\). [2]
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Easiest question Easy -1.8 »
Simplify \(( 3 + \sqrt { } 5 ) ( 3 - \sqrt { } 5 )\). \includegraphics[max width=\textwidth, alt={}, center]{c0db3fe8-62ec-41e3-acaf-66b2c7b2754d-02_108_93_2614_1786}
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Hardest question Moderate -0.3 »
2. (a) Expand \(( 2 \sqrt { } x + 3 ) ^ { 2 }\).
(b) Hence evaluate \(\int _ { 1 } ^ { 2 } ( 2 \sqrt { } x + 3 ) ^ { 2 } \mathrm {~d} x\), giving your answer in the form \(a + b \sqrt { } 2\), where \(a\) and \(b\) are integers.
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Solve power equations

A question is this type if and only if it requires solving an equation where the variable is raised to a power, such as x^(3.9) = 11x^(3.2) or x^(2/3) + 3x^(1/3) - 10 = 0.

23 Easy -1.0
7.1% of questions
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Make \(a\) the subject of \(3(a + 4) = ac + 5f\). [4]
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Easiest question Easy -1.8 »
1 Solve the equations
  1. \(x ^ { \frac { 1 } { 3 } } = 2\),
  2. \(10 ^ { \prime } = 1\),
  3. \(\left( y ^ { - 2 } \right) ^ { 2 } = \frac { 1 } { 81 }\).
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Hardest question Moderate -0.3 »
6. $$f ( x ) = x ^ { \frac { 3 } { 2 } } - 8 x ^ { - \frac { 1 } { 2 } }$$
  1. Evaluate \(\mathrm { f } ( 3 )\), giving your answer in its simplest form with a rational denominator.
  2. Solve the equation \(\mathrm { f } ( x ) = 0\), giving your answers in the form \(k \sqrt { 2 }\).
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Express in form with given base

A question is this type if and only if it asks to rewrite an expression as a power of a specified base, such as expressing 125√5 in the form 5^k or 8^(2x+3) in the form 2^y.

19 Easy -1.4
5.8% of questions
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2. Given that \(32 \sqrt { } 2 = 2 ^ { a }\), find the value of \(a\).
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Easiest question Easy -1.8 »
2. Given that \(32 \sqrt { } 2 = 2 ^ { a }\), find the value of \(a\).
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Hardest question Moderate -0.8 »
  1. Find the value of \(a\) and the value of \(b\) for which \(\frac { 8 ^ { x } } { 2 ^ { x - 1 } } \equiv 2 ^ { a x + b }\)
  2. Hence solve the equation \(\frac { 8 ^ { x } } { 2 ^ { x - 1 } } = 2 \sqrt { 2 }\)
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Show surd expression equals value

A question is this type if and only if it asks to prove or show that a specific surd expression simplifies to a given value or form, such as showing (√180 - √80)/√5 is an integer.

17 Easy -1.1
5.2% of questions
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1 Show that \(\frac { 31 } { 6 - \sqrt { 5 } } = 6 + \sqrt { 5 }\).
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Easiest question Easy -1.8 »
5 Show that the distance between the points \(( 5,2 )\) and \(( 11 , - 1 )\) is \(a \sqrt { b }\), where \(a\) and \(b\) are integers to be determined.
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Hardest question Standard +0.3 »
Show that $$\frac{3 + \sqrt{8n}}{1 + \sqrt{2n}}$$ can be written as $$\frac{4n - 3 + \sqrt{2n}}{2n - 1}$$ where \(n\) is a positive integer. [4 marks]
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Solve exponential equations

A question is this type if and only if it requires solving an equation where the variable appears in an exponent, such as 3^(6x-3) = 81 or 4^(2x+1) = 8^(4x), typically by expressing both sides with the same base.

16 Easy -1.0
4.9% of questions
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Find the value of \(y\) such that $$4^{y + 3} = 8.$$ [3]
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Easiest question Easy -1.3 »
  1. (i) Simplify
$$\sqrt { 48 } - \frac { 6 } { \sqrt { 3 } }$$ Write your answer in the form \(a \sqrt { 3 }\), where \(a\) is an integer to be found.
(ii) Solve the equation $$3 ^ { 6 x - 3 } = 81$$ Write your answer as a rational number.
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Hardest question Moderate -0.5 »
1 Find the set of values of \(x\) for which \(3 \left( 2 ^ { 3 x + 1 } \right) < 8\). Give your answer in a simplified exact form.
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Simplify numerical surds

A question is this type if and only if it asks to simplify a numerical expression involving square roots into the form k√n, such as √45 + √20 or √180 - √80.

15 Easy -1.5
4.6% of questions
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Express \(\sqrt{22.5}\) in the form \(k\sqrt{10}\). [4]
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Easiest question Easy -1.8 »
  1. Write
$$\sqrt { } ( 75 ) - \sqrt { } ( 27 )$$ in the form \(k \sqrt { } x\), where \(k\) and \(x\) are integers.
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Hardest question Easy -1.2 »
1 Express \(\sqrt { 45 } + \frac { 20 } { \sqrt { 5 } }\) in the form \(k \sqrt { 5 }\), where \(k\) is an integer.
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Solve equations with surds

A question is this type if and only if it requires solving an equation containing surds, such as x√3 - 3 = x + √3 or 4x = 2√2x + 20√2, with the answer in surd form.

15 Moderate -0.8
4.6% of questions
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1 Solve the equation $$x \sqrt { 32 } - \sqrt { 24 } = ( 3 \sqrt { 3 } - 5 ) ( \sqrt { 6 } + x \sqrt { 2 } )$$
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Easiest question Easy -1.3 »
  1. (a) Evaluate \(\left( 5 \frac { 4 } { 9 } \right) ^ { - \frac { 1 } { 2 } }\).
    (b) Find the value of \(x\) such that
$$\frac { 1 + x } { x } = \sqrt { 3 }$$ giving your answer in the form \(a + b \sqrt { 3 }\) where \(a\) and \(b\) are rational.
[0pt]
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Hardest question Moderate -0.3 »
2 In this question you must show detailed reasoning. Solve the equation \(x \sqrt { 5 } + 32 = x \sqrt { 45 } + 2 x\). Give your answer in the form \(a \sqrt { 5 } + b\), where \(a\) and \(b\) are integers to be determined.
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Differentiate after index conversion

A question is this type if and only if it requires first converting an expression to index form (typically Ax^p + Bx^q) and then differentiating with respect to x.

8 Moderate -0.5
2.5% of questions
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8. $$f ( x ) = \frac { \left( x ^ { 2 } - 3 \right) ^ { 2 } } { x ^ { 3 } } , x \neq 0$$
  1. Show that \(\mathrm { f } ( x ) \equiv x - 6 x ^ { - 1 } + 9 x ^ { - 3 }\).
  2. Hence, or otherwise, differentiate \(\mathrm { f } ( x )\) with respect to \(x\). END
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Express in terms of substitution

A question is this type if and only if it provides a substitution like y = 2^x or m = 2^n and asks to express other exponential expressions in terms of the new variable.

4 Easy -1.1
1.2% of questions
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  1. Given
$$\frac { 3 ^ { x } } { 3 ^ { 4 y } } = 27 \sqrt { 3 }$$ find \(y\) as a simplified function of \(x\).
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Rewrite with fractional indices

A question is this type if and only if it asks to rewrite an expression involving roots and powers in the form Ax^p + Bx^q, such as converting (5x^2 + √(x^3))/∛(8x) to this form.

4 Easy -1.1
1.2% of questions
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Express $$5 - \frac{\sqrt[3]{x}}{x^2}$$ in the form $$5x^p - x^q$$ where \(p\) and \(q\) are constants. [2 marks]
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Rationalize denominator two surds

A question is this type if and only if it asks to rationalize a denominator containing two different surds, such as (8 - √15)/(2√3 + √5), resulting in the form a√m + b√n.

3 Moderate -0.8
0.9% of questions
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Express \(\frac{\sqrt{3} + 3\sqrt{5}}{\sqrt{5} - \sqrt{3}}\) in the form \(a + b\sqrt{c}\), where \(a\) and \(b\) are integers. Fully justify your answer. [4 marks]
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Expand polynomial with surds

A question is this type if and only if it asks to expand and simplify a polynomial expression containing surds into the form ax^2 + bx√c + d, such as f(x) = (x + √2)^2 + (3x - 5√8)^2.

2 Moderate -1.0
0.6% of questions
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1. $$f ( x ) = ( \sqrt { x } + 3 ) ^ { 2 } + ( 1 - 3 \sqrt { x } ) ^ { 2 }$$ Show that \(\mathrm { f } ( x )\) can be written in the form \(a x + b\) where \(a\) and \(b\) are integers to be found.
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Simplify using given results

A question is this type if and only if it asks to use results from previous parts to prove or simplify a more complex expression, such as using (r - 1/r)^2 and 1/(3 + 2√2) to show a specific identity.

1 Moderate -0.8
0.3% of questions
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  1. In this question you must show all stages of your working. Solutions relying on calculator technology are not acceptable.
    1. Expand and simplify
    $$\left( r - \frac { 1 } { r } \right) ^ { 2 }$$
  2. Express \(\frac { 1 } { 3 + 2 \sqrt { 2 } }\) in the form \(p + q \sqrt { 2 }\) where \(p\) and \(q\) are integers.
  3. Use the results of parts (a) and (b), or otherwise, to show that $$\sqrt { 3 + 2 \sqrt { 2 } } - \frac { 1 } { \sqrt { 3 + 2 \sqrt { 2 } } } = 2$$
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Find constants in identity

A question is this type if and only if it asks to find the values of constants (typically a, b, c, k, n, p, q) that make an algebraic or exponential identity true, such as (3pq^2)^4 × 2p√(q^8) ≡ ap^bq^c.

1 Easy -1.2
0.3% of questions
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  1. Given that
$$\left( 3 p q ^ { 2 } \right) ^ { 4 } \times 2 p \sqrt { q ^ { 8 } } \equiv a p ^ { b } q ^ { c }$$ find the values of the constants \(a , b\) and \(c\).
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