Resolva, em R, as inequações:
a) 4 < x2 < 9 b) -2 < x2 – 2 < 2
Obrigada
a) 4 < x² < 9
√4 < √x² < √9
2 < x < 9
b) -2 < x² -2 < 2
-2 (+ 2)< x² - 2 (+ 2) < 2 (+ 2)
0 < x² < 4
√0 < √x² < √4
x < 2.
Comments
a) 4 < x² < 9
√4 < √x² < √9
2 < x < 9
b) -2 < x² -2 < 2
-2 (+ 2)< x² - 2 (+ 2) < 2 (+ 2)
0 < x² < 4
√0 < √x² < √4
x < 2.