I can't figure out how d is wrong

This problem concerns the integral dx, x2+ 4x + 13 which can be solved using various methods. Show how to solve it using a trigonometric substitution, by completing the steps below. (a) This integral can be evaluated using a single trigonometric substitution, which can be written in the form x = h(t), where h(t) = 3tan(t)-2 (b) Applying the substitution in (a) and simplifying leads to x2 + 4x + 13 dac = / 9(t ) at, where g(t) = tan(t)-(2/3) (c) Evaluate S g(t) dt: g(t) at = -In|cos(t)|-2/3(t) + C (d) Finally, solve the original integral: dx = 2 + 4x + 13 -3In|sqrt(x^2+4x+13)| -2(arctan((x+2)/3)) + C