We have described the slope of an indifference curve as the marginal rate of substitution between the two goods. Imagining that c is plotted on the vertical axis and c plotted on the horizontal axis, compute the marginal rate of substitution for the following utility functions. a. u(c,c)=ln(c)+ In(c) b. u(, c) = + 1-a c. u(c,c) = cca, where a = (0,1) is some constant.