18. (9 points) The angle between two vectors x and y of length n can be computed from the identity yCos()al where 1/2 rn A programmer wrote the following function to compute the angle (in radians): double angle (double *x, double *y, int n) double norm_x -0.0, norm_y - 0.0, dot-0.0; int i; for (i-1;i