A.轉(zhuǎn)轍角的余切 B.轉(zhuǎn)轍角的正切 C.轍叉角的余切 D.轍叉角的正切
A.s/2 B.s/4 C.s/3
A.1:1.5 B.1:1.75 C.1:2.0 D.1:2.25