Solve the following equations for x: (i) tan−12x + tan−13x = nπ + 3π4 (ii) tan−1(x + 1) + tan−1(x − 1) = tan−1831 (iii) tan-114+2 tan-115+tan-116+tan-11x=π4 (iv) sin−1x + sin−12x = π3 (v) 3 sin-12x1+x2-4 cos-11-x21+x2+2 tan-12x1-x2=π3 (vi) cos-1x+sin-1x2=π6 (vii) tan−1(x −1) + tan−1x tan−1(x + 1) = tan−13x (viii) tan (cos−1x) = sincot-112 (ix) tan−11-x1+x-12tan−1x = 0, where x > 0 (x) cot−1x − cot−1(x + 2) = π12, x > 0 (xi) tan-12x1-x2+cot-11-x22x=2π3, x>0 (xii) tan−1(x + 2) + tan−1(x − 2) = tan−1879, x > 0 (xiii) tan-1x2+tan-1x3=π4, 0<x<6