sin \frac{π}{4} = \frac{\sqrt{2}}{2}
cos \frac{π}{4} = \frac{\sqrt{2}}{2}
sin \frac{π}{4} + cos \frac{π}{4} = \frac{\sqrt{2}}{2} + \frac{\sqrt{2}}{2} = \frac{2\sqrt{2}}{2} = \sqrt{2}
Ответ: $$\sqrt{2}$$