Question

Se considera numerele reale>
x= $-4 \sqrt{15}$
si y= $2 \sqrt{3}$
Calculati: a) |x|
b) [$2 \sqrt{3}$ ]
c) x*y
d) x:y
e) y^3
f) x^-2

Answer 1

[tex] |x|=4 \sqrt{15} \\ b) \\ \lbrack {2 \sqrt{3} \rbrack=? \Longleftrightarrow \lbrack { \sqrt{8}\rbrack=? \Rightarrow \sqrt{4}\ \textless \ \sqrt{8}\ \textless \ \sqrt{9} \Rightarrow 2 \ \textless \ \sqrt{8}\ \textless \ 3 \Rightarrow \lbrack{2\sqrt{3}\rbrack=2[/tex]
$c) \\ x*y=-4\sqrt{15}*2\sqrt{3}=-8\sqrt{45}$
$d) \\ x:y= -4\sqrt{15}:2\sqrt{3}=-2\sqrt{5} = -\sqrt{20}$
$e) \\ y^3=(-4\sqrt{15})^3=(-4\sqrt{15})^2*-4\sqrt15=16*15*-4\sqrt{15}=-960\sqrt15$
$f) \\ a^{-n}=\frac{1}{a^{n}} \\ x^{-2}=(2\sqrt{3})^{-2}= \frac{1}{(2\sqrt{3})^2}=\frac{1}{4*3}=\frac{1}{12},$

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