an optical system consists of an optical lens and a concavemirror, the focal length of length is f=20​cm, the distance betweenobjective and lens is 30, the distance between lens and concavemirro is alos 30cm, the radius of concave mirror is 30cm.
​(a) find the location of the final image
​(b)is this a real or virtual image?
​(c)is this an erect or inverted image?
​(d)what is the overall transversal magnification?
