Question

VREAU EX E4 PUNCTELE A,B,C
PLEASEEEEEE
E URGENT!!!!!!!​

Answer 1

Explicație pas cu pas:

c)

$\Big|1 - \dfrac{ {n}^{2} + 2 }{{n}^{2} + 1} \Big| = \Big|1 - \dfrac{ {n}^{2} + 1 + 1 }{{n}^{2} + 1} \Big| = \Big|1 - 1 - \dfrac{1 }{{n}^{2} + 1} \Big| = \Big|- \dfrac{1 }{{n}^{2} + 1} \Big| = \dfrac{1 }{{n}^{2} + 1}$

$\dfrac{1 }{{n}^{2} + 1} \geqslant \dfrac{1}{10} \iff {n}^{2} + 1 \leqslant 10$

${n}^{2} \leqslant 9 \implies {n}^{2} \leqslant {3}^{2} \iff - 3 \leqslant n \leqslant 3 \\ \implies n \in \Big\{- 3; - 2; - 1; 0; 1; 2; 3; \Big\}$