y > -\sqrt{\frac{6a+b}{2b}} - xc\newline with : -\frac{a^2 + d^2}{c} \le x \le \frac{a^2 + d^2}{c}\newline y < \sqrt{a^2 + d^2}\newline Value of : a = n + 3. With n is a vector unit. Known \vec{u} = \vec{i} + 2\vec{j} - \vec{k} and \vec{v} = \vec{i} + \vec{j} + n\vec{k}.\newline The vector projection P_v(u) of u onto v = \frac{2}{\pi}\sqrt{3}.\newline with n \ge 0.\newline b, is from the solution of : \newline \frac{1}{x^2+x} + \frac{1}{x^2+3x+2} + \frac{1}{x^2+5x+6} + ... + \frac{1}{x^2+21x+110} = \frac{11}{bx^2+11x}\newline e, is from sequence C_n, with a_1 = 2 and a_{n+2}\newline a_{n+1} = a_n + 2n, for n \ge 1, then a_{100} = 9900 + c\newline d = 6(m+n) With m, n are the solution of\newline trigonometric equation:\newline cos \cdot cos x = \sqrt{m} + \sqrt{n} and sin \cdot sin x = \sqrt{m} - \sqrt{n}.
