SinA×CosA=60/169,
(SinA+CosA)^2=SinA^2+CosA^2+2SinA×CosA=1+120/169 =289/169,
(SinA-CosA)^2=SinA^2+CosA^2-2SinA×CosA=1-120/169 =49/169,
45度
SinA×CosA=60/169,
(SinA+CosA)^2=SinA^2+CosA^2+2SinA×CosA=1+120/169 =289/169,
(SinA-CosA)^2=SinA^2+CosA^2-2SinA×CosA=1-120/169 =49/169,
45度