Question

1)Rezultatul caulcului  sin 60+sin30/cos30-cos60
2)Determina x si y ,astfel incat x^2+y^2-4x+6y+10=-3

Answer 1

1) sin 60= √3/2
cos 60= 1/2

sin 30= 1/2
cos 30= √3/2

√3/2 + 1/2/√3/2 -1/2=  √3/2 + 1/2 * 2/√3 -1/2=

= √3/2 + 1/√3 -1/2=     rationalizam

=√3/2 +√3/3 -1/2   aducem la acelasi numitor

=(3√3+2√3-3)/6=  (5√3-3)/6

2)x²-4x +4 +y²+6y+9 -3=-3
(x-2)²+(y+3)²-3+3=0

(x-2)² +(y+3)²=0

x-2=0   y+3=0
x=2       y= -3