Question

Va roggg repede dau si coroana

Answer 1

a)Subunitara : 12 < 2n+4 =>2n > 8 =>n > 4
n € {5, 6, 7, ...}
Echiunitara : 12 = 2n+4 =>2n=8 =>n=4
b)Supraunitara : 3n+2 > 2n+7 =>n > 5
n € {6, 7, 8, ...}
Echiunitara : 3n+2=2n+7 =>n=5

Answer 2

Răspuns

Explicație pas cu pas:

a)  12 / ( 2 n + 4 ) → fractie subunitara ( numaratorul < numitorul )

2 n + 4 > 12

2 n > 12 - 4

2 n > 8  ⇒   n > 8 : 2  ⇒   n > 4 ⇒  n = 5,  6,   7,   8,  ........

Verific:  

n = 5 ⇒   12 / ( 2 × 5 + 4 ) = 12 / 14 → fractie subunitara

n = 6 ⇒   12 / ( 2 × 6 + 4 ) = 12 / 16

n = 7 ⇒  12 / 18

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12 / ( 2 n + 4 ) → fractie echiunitara  ( numaratorul = numitorul )

2 n + 4 = 12

2 n = 12 - 4

2 n = 8

n = 8 : 2

n = 4

V:  12 / ( 2 × 4 + 4 ) = 12 / 12

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b)   ( 3 n + 2 ) / ( 2 n + 7 ) → fractie supraunitara ( numaratorul > numitorul )

3 n + 2 > 2 n + 7

3 n - 2 n > 7 - 2

n > 5 ⇒  n = 6,  7,   8,   9, ......

n = 6 ⇒ ( 3 × 6 + 2 ) / ( 2 × 6 + 7 ) = 20 / 19 → fractie supraunitara

n = 7 ⇒ ( 3 × 7 + 2 ) / ( 2 × 7 + 7 ) = 23 / 21 → fractie supraunitara

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( 3 n + 2 ) / ( 2 x + 7 ) → fractie echiunitara ( numitorul = numaratorul A)

3 n + 2 = 2 n + 7

3 n - 2 n = 7 - 2

n = 5

Verific:   ( 3 × 5 + 2 ) / ( 2 × 5 + 7 ) = 17 / 17 → fractie echiunitara