Jeżeli α=135°, to :
A) sin α = cos α
B) tg α > cos α
C) cos α >sin α
C) tg α < cos α


Odpowiedź :

Odpowiedż:

C)

Wyjaśnienie:

[tex]sin135^{o} = sin(90^{o}+45^{o}) = cos45^{o} = \frac{\sqrt{2}}{2}\\\\cos135^{o} = cos(90^{o}+45^{o}) = -sin45^{o} = -\frac{\sqrt{2}}{2}\\\\tg135^{o} = tg(90^{o}+45^{o}) = -ctg45=-1\\\\ctg135^{o} = ctg(90^{o}+45^{o}) = -tg45^{o} = -1\\\\cos135^{o} < sin135^{o}\\cos\alpha < sin\alpha[/tex]