Question

помогите пожалуйста!!!
2 задание не надо ​

Answer 1

$1)\; \; \Delta PCB\; ,\; \angle P=90^\circ \\\\sinC=\frac{BP}{BC}\; \; ,\; \; cosC=\frac{CP}{BC}\; \; ,\; \; tgB=\frac{CP}{BP}\; \; ,\; \; ctgB=\frac{BP}{CP}\\\\\\3)\; \; sina=\frac{4}{5}\\\\sin^2a+cos^2a=1\; \; \to \; \; \; cosa=\pm \sqrt{1-sin^2a}=\pm \sqrt{1-\frac{16}{25}}=\pm \frac{3}{5}\\\\tga=\frac{sina}{cosa}=\frac{4}{5}:(\pm \frac{3}{5})=\pm \frac{4}{3}\\\\ctga=\frac{1}{tga}=\pm \frac{3}{4}$

$4)\; \; \alpha =60^\circ\; \; \Rightarrow \; \; \; \beta =90^\circ -60^\circ =30^\circ \\\\a=12\cdot cos60^\circ =12\cdot \frac{1}{2}=6\\\\b=12\cdot sin60^\circ =12\cdot \frac{\sqrt3}{2}=6\sqrt3$