Oblicz tgx

[natasza99]

Oblicz \(\displaystyle{ tgx}\),wiedząc, że \(\displaystyle{ siny = \frac{1}{\sqrt{10}}}\) i \(\displaystyle{ x+2y= \frac{\pi}{4}}\)
i \(\displaystyle{ x,y \in ( 0, \frac{\pi}{2})}\)

[piasek101]

Zatem :
\(\displaystyle{ cosy=\frac{3}{\sqrt{10}}}\)

\(\displaystyle{ sin(2y)=\frac{3}{5}}\)

\(\displaystyle{ cos(2y)=\frac{4}{5}}\)

\(\displaystyle{ sinx=sin(45^0-2y)}\) (mając sinus wyznaczyć kosinusa i dokończyć)