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IGCSE Math B1.D SurdsTopic Practice

1.D Surds

Simple manipulation of surds Students should understand what surds represent and their use for exact answers Manipulation will be simple 53 23 73 48 4 3 110 2 5 += = x=

Question 9

Without using a calculator, find the value of 12+30027\frac{\sqrt{12}+\sqrt{300}}{\sqrt{27}}
Show your working clearly.

Question 10

Without using a calculator and showing your working clearly, find the value of the integer a so that
1802720+147=a(5+3).\sqrt{180}-\sqrt{27}-\sqrt{20}+\sqrt{147}=a(\sqrt5+\sqrt3).

Question 8

Given that a=(73)\mathbf a=\binom{7}{-3}, find the exact value of a|\mathbf a|.

Question 14

[Maximum number: 3]

Here is a right-angled triangle.

Question image

Given that tanθ=8\tan \theta=\sqrt{8}
express 3(sinθ+cosθ)3(\sin \theta+\cos \theta) in the form m+nm+\sqrt{n} where m and n are integers.
Show your working clearly.

Diagram NOT accurately drawn

Question 15

Without using a calculator and showing all your working, express
318022453\sqrt{180}-2\sqrt{245}
in the form a\sqrt{a}, where a is an integer.

Question 18

Express
35+3527652\frac{\sqrt{35}+3\sqrt5-2\sqrt7-6}{\sqrt5-2}
in the form m+nm+\sqrt n, where m and n are integers.
Show your working clearly.

Question 11(c)

[Maximum number: 2]
Question image

Diagram NOT accurately drawn.

Figure 3 shows triangle ABC.
AB=43 cm,BC=35 cm,AC=x cm,BAC=15.AB=4\sqrt3\text{ cm},\quad BC=3\sqrt5\text{ cm},\quad AC=x\text{ cm},\quad \angle BAC=15^\circ.
Given that the exact value of cos15=6+24\cos15^\circ=\frac{\sqrt6+\sqrt2}{4}.

Show that (3+23)2=21+123(3+2\sqrt3)^2=21+12\sqrt3.

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