a) [tex] 2 \ \textless \ \sqrt{7} \ \textless \ 3 [/tex] (ridici totul la patrat)
4 < 7 < 9 - Adevarat
b) [tex]-4 \ \textless \ -\sqrt{10} \ \textless \ -3 [/tex] | x (-1)
[tex]3 \ \textless \ \sqrt{10} \ \textless \ 4 [/tex] (ridici la patrat)
9 < 10 < 16 - Adevarat
c) [tex] \sqrt{0,4} = \sqrt( \frac{4}{10} ) = \frac{ \sqrt{4} }{ \sqrt{10} } = \frac{2}{ \sqrt{10} } [/tex] ∉ Q - Fals
d) [tex] \sqrt{0,14} = \sqrt{ \frac{14}{100} } = \frac{ \sqrt{14}}{ \sqrt{100}} = \frac{ \sqrt{14}}{10} [/tex] ∉ Q - Fals
e) [tex] \sqrt{2,25} = \sqrt{ \frac{225}{100}} = \frac{ \sqrt{225}}{ \sqrt{100}} = \frac{15}{10} = \frac{3}{2} [/tex] ∉ R\Q - Fals
f) [tex] \sqrt{1,6} = \frac{ \sqrt{16} }{ \sqrt{10} } = \frac{4}{ \sqrt{10} } [/tex]∈R\Q - Adevarat
g) [tex] \sqrt{0.16} = \frac{ \sqrt{16} }{ \sqrt{100} } = \frac{4}{10} = \frac{2}{5} [/tex]∈Q - Adevarat
h) [tex] \sqrt{0.(16)} = \frac{ \sqrt{16} }{ \sqrt{99} } = \frac{4}{ \sqrt{99} } [/tex]∉Q - Fals
i) Rezolvam intain suma
S = 1+3+ 5+...+11
nr. termeni = (11-1):2+1 = 10:2+1= 5+1 = 6
S= [tex] \frac{(11+1)*6}{2} = \frac{12*6}{2} = 6*6 = 36
[/tex]
[tex] \sqrt{S} = \sqrt{36} = 6 [/tex]∈Q - Adevarat
