Let a be a positive real number and let j be the closed interval π 6 −a, π 6 +a . use the tangent line error bound to verify that |f(x)−t1(x)|≤ a2 2 for all x in j. use this error bound to find a value of a so that |f(x)−t1(x)|≤ 0.01 for all x in j. (round your answer to four decimal places.) a=