Question

Решите систему уравнения x+y=pi/4; tg x * tg y = 1/6

Answer 1

$\left \{ {{x+y= \frac{ \pi }{4} } \atop {tg x\cdot tg y= \frac{1}{6} }} \right. \to \left \{ {{x=\frac{ \pi }{4}-y} \atop {tg(\frac{ \pi }{4}-y)\cdot tgy = \frac{1}{6} }} \right. \\ \\ \frac{1-tg y}{1+tgy}\cdot tg y= \frac{1}{6} \\ \\ 6tg^2y-5tg y+1=0 \\ D=b^2-4ac=25-24=1 \\ tgy= \frac{5+1}{12} = \frac{1}{2} ;\to y_1=arctg \frac{1}{2}+ \pi n \\ tgy= \frac{5-1}{12} = \frac{1}{3} ;\to y_2=arctg \frac{1}{3} + \pi n \\ x_1=\frac{ \pi }{4}-arctg \frac{1}{2} - \pi n$
$x_2=\frac{ \pi }{4}-arctg \frac{1}{3} - \pi n$