Problem 3. A dentist uses a curved mirror to view teeth on the upper side of the mouth. Suppose she wants an erect (upward) image with a magnication of 2.00 when the mirror is 1.25 cm. from a tooth. (treat this problem as the object and the image lie along a straight line). (a) What king of mirror, convex or concave, is needed. Use a ray diagram to decide, without performing any calculations. (b) What must be the focal length and radius of curvature of this mirror