Question

a expressao (pi - x) - cos (pi/2 + x) esquivale a : a) 2senx b) -2 sen x c) sen x + cos x d) sen x - cos x e) 2 cos x

Answer 1

Olá, Laura.

 

$<var>cos(\pi - x) - cos (\frac{\pi}2 + x)=</var>$

 

$=<var>cos\pi\ cos\ x-sen\pi\ sen\ x-(cos\frac{\pi}2\ cos\ x-sen\frac{\pi}2\ sen\ x)=</var>$

 

$<var>=-1 \cdot cos\ x-0 \cdot sen\ x - 0\cdot cos\ x+1 \cdot sen\ x = sen\ x - cos\ x</var>$

 

Resposta: letra "d"