For the function f(x) = x + 3x: a. Calculate and simplify: msec f(x+h)-f(x) (x+h)-(x) b. Determine mtan = lim h0 msec c. Evaluate mtan at x = 2 d. Find an equation of the line tangent to the graph of fat (2, 10) f(x) For what values of A and B is f(x) differentiable at x = 1, where f(x) is defined below? What is the value of the derivative at x = 1? Ax+B if x < 1 x+x if x 21