Răspuns :
Răspuns
Asta ar fi o idee.
Explicație pas cu pas:
[tex]tg \frac{x}{2} = \frac{sin\frac{x}{2} }{cos\frac{x}{2}}[/tex]
[tex]sinx=2sin\frac{x}{2}cos\frac{x}{2}=2 tg\frac{x}{2}cos^2\frac{x}{2}[/tex]
[tex]cosx= 1- sin^2\frac{x}{2} = 1-(tg\frac{x}{2}cos\frac{x}{2} )^2[/tex]
[tex]\it sinx=\dfrac{2t}{1+t^2}\\ \\ \\ cosx=\dfrac{1-t^2}{1+t^2}[/tex]