1. The problem statement, all variables and given/known data A trucker sees the image of a car passing her truck in her diverging rear view mirror whose focal length is -60cm. If the car is 1.5m high and 6.0m away, what is the size and location of the image? 2. Relevant equations 1/f = 1/di + 1/do 3. The attempt at a solution Finding the di The solution I come up with is: 1/-0.6 = 1/di + 1/6 -1.66 - 0.166 = 1/di di = -0.5454 The correct answer in my book is : 1/-0.6 = 1/di + 1/-6 -1.66 + 0.166 = 1/di di = -0.66 Why is the distance to the object negative? This does not agree with sign convention (as stated in my book) "Distances of real objects and images are positive"