Pronos Évals

 

Corrigé exo 1 :

 

1.cos(π − x )+ cos(x + 3π)= −cos(x )+ cos(x + π)= −cos(x )− cos(x )= −2cos(x ).

2. sin(−x)−sin(3π+x)=−sin(x)−sin(π+x)=−sin(x)+sin(x)=0.

3. −sin(x − 3π)+ sin(4π − x )= −sin(x − π)+ sin(−x )= sin(x )− sin(x )= 0.

Donc : cos(−π − x )− sin(x − 3π)+ sin(4π − x )= cos(π − x )+ 0 = −cos(x ).