Approximate the value of the given integral by completing parts (a) and (b) below. (a) Use the trapezoidal rule, using n = 4. (b) Check by direct integration. IN 6x dx (a) Use the trapezoidal rule to approximate the integral. (Type an integer or a decimal.) (b) Find the exact value of the integral by integration. 6x2 dx = (Type an integer or decimal rounded to two decimal places as needed.)