I know when I find T_n(x) of f(x)= x cos(4x) , where a=0, n=5, and -0.3 <= x <= 0.3 the taylor series expansion is

T₅(x) = x - 8x³ + (32/3)x⁵

But how do I investigate the accuracy of my approximation by finding an upper bound for abs[R_n(x)] when x lies in the given interval? to 6 decimal places.....