7. Let f(x) = 1 (a) (5 points) Calculate f'(1) by using the limit definition of the derivative. If you get the wrong answer using the limit, then you can simply state the derivative using the derivative rules for 1 point. Show all work and use proper notation. (b) (4 points) Use your answer from part (a) to find the equation of the tangent line to f(r) at r=1.