3.1.38 Curves of the 2 -nd Order

Condition: Determine the large half -suction of the ellipse \ (\ frac {x^{2}} {a^{2}+\ frac {y^{2}} {144} = 1 \) if the line passing through its left focus is perpendicular to the direct \ (x+2 y+1 = 0 \ 0 \ 0 \ 0 \) passes through Point \ (A (-2.6) \).