Odpowiedź:
Zadanie 1
sin 225°= sin (3*90°-45°)= - cos45°= - √2/2
ctg 330°= ctg (4*90°-30°)= - ctg30°= -√3
tg 450°= tg (4*90°-90°)= tg90°= 0
sin² 225°= (sin 225°)²= ( -√2/2)²= 2/4= 1/2
2 sin²225° - ctg 330° · tg 450° = 2 *1/2 - (-√3)*0= 1+√3*0= 1+0= 1
Zadanie 2
P= (-5,2)
x= -5
y= 2
r²= x²+y²
r²= (-5)²+2²
r²= 25+4
r²= 29
r=√29
sinα= y/r
sinα= 2/√29 *√29/√29= 2√29/29
cosα= x/r
cosα= -5/√29 *√29/√29= -5√29/29
tgα= y/x = -2/5
ctgα= x/y= -5/2
