(1) Sin²O+ sind
= cos + cos =1
sin²0+sin° 0+sin*8=
(2) Sin² +sin & (sin² + sin")
(3) cos 0 =
sind+sin(sing + cos²0) = sin²+sing x1 = sino+cust-11 x+x-1=0-
21.如右圖,OP=OQ,QR - PR,∠QOR=日,若cos=
Altan-
5
2
4
22.銳角△ABC中,cos/ABC-
1
Da
R
2
(算不祫)
91
50元硬幣2枚,10元
co12 oftas
09-01+05
(格刮刮卷每張有9個小
10+10=204