Respuesta :

mhanifa

Answer:

  • b, c, d

Step-by-step explanation:

a. tan 30/ sin 30 = (sin 30/cos 30) / sin 30 = 1 / cos 30, no

b. cos 30 = √3/2, yes

c. cos 60 tan 60 = cos 60 (sin 60/cos 60) = sin 60 = cos 30, yes

d. sin 60 = cos (90 - 60) = cos 30, yes

[tex]\bf{b.}\ \ \it cos30^o=\dfrac{\sqrt3}{2}\ \ (True)\\ \\ \bf{d.}\ \ \it sin60^o=cos(90^o-60^o)=cos30^o\ \ (True) \\ \\ \bf{c.}\ \it cos60^o\cdot tan60^o=cos60^o\cdot\dfrac{sin60^o}{cos60^o}=\dfrac{cos60^o}{cos60^o}\cdot sin60^o=1\cdot sin60^o=cos30^o\ (T)\\ \\ \\ \bf{a.}\ \ \it \dfrac{tan30^o}{sin30^o}=tan30^o\cdot\dfrac{1}{sin30^o}=\dfrac{sin30^o}{cos30^o}\cdot\dfrac{1}{sin30^o}=\dfrac{sin30^o}{sin30^o}\cdot\dfrac{1}{cos30^o}=\\ \\ \\ =1\cdot\dfrac{1}{cos30^o}=\dfrac{1}{cos30^o}\ \ne\ cos30^o[/tex]

Otras preguntas