Question

2cos(a/2) = $\sqrt{2+2cosa}$

Answer 1

Răspuns:

Notez a= 2t

2*cos(2t/2) = rad( 2 + 2*cos(2t) )

[2*cos(t) ]² = 2 + 2*cos(2t)

4*cos(t)² = 2 + 2*[ 2*cos(t)² -1 ]

4*cos(t)² = 2 + 4*cos(t) - 2

4*cos(t)² = 4*cos(t)²

4*cos(a/2)² = 4*cos(a/2)²