Recent content by ilovemycat

yes, i have not been asked to provide a ray diagram. heres the graph i made: unsure how to find focal length just graphically...

So I have plotted all the given data points on a graph, putting 1/di on the y- axis and 1/do on the x-axis. I have to now find focal length from the graph? I'm not sure how, I'm thinking I have to rearrange the equation 1/f = 1/do + 1/di into y = mx + b form then go from there, but I'm totally...