Question

daca sin x + sin y =-14/65 si cos x + cos y =-8/65. calculati tg(x+y)

Answer 1

Răspuns:

Explicație pas cu pas:

sinx +siny = 2sin(x+y)/2*cos(x-y)/2= -14/65

cosx +cosy = 2cos(x+y)/2*cos(x-y)/2= -8/65

Le impartim:

tg(x+y)/2 = -145/65*(-65/8)=14/8= 7/4

Dar tg(x+y) = (2tg((x+y)/2))/((1-(tg((x+y)/2))^2)

tg(x+y) = (2*7/4)/(1-49/16)

tg(x+y = 7/2*(-16/33) = -56/33