As shown in the figure, the center of the small circle is at the origin, the radius is 3, the center coordinates of the big circle are (a, 0) and the radius is 5. If there are two circles, then the value range of a is______ .

As shown in the figure, the center of the small circle is at the origin, the radius is 3, the center coordinates of the big circle are (a, 0) and the radius is 5. If there are two circles, then the value range of a is______ .

According to the center coordinates of the two circles, the center distance of the circle = | A-0 | = | a |, because when the two circles contain, the center distance of the circle is less than 5-3, that is | a | < 2, and the solution is - 2 | a | < 2