## Trigonometry 7th Edition

$\large(\frac{\sqrt{2}}{2},-\frac{\sqrt{2}}{2}), (-\frac{\sqrt{2}}{2},\frac{\sqrt{2}}{2})$
Plugging in $y =-x$ in the equation $x^2+y^2 =1$ $$x^2+(-x)^2=1\\2x^2=1\\x^2=\frac{1}{2}$$ $$\therefore x=\pm \frac{\sqrt{2}}{2}$$ $$\therefore y=-x = \mp \frac{\sqrt{2}}{2}$$ The coordinates of the points of intersection are $\large(\frac{\sqrt{2}}{2},-\frac{\sqrt{2}}{2})$ and $\large(-\frac{\sqrt{2}}{2},\frac{\sqrt{2}}{2})$.