數學問題,人地話呢條好難

I think 派 means π
cos(3π/2+A)/tan (A-π)+1/tan(π/2-A)-cos (A-2π)
=sin A/tan[2π-(π-A)]+tan A-cos[2π-(2π-A)]
=sin A/tan (π+A)+tan A-cos A
=sin A/tan A+tan A-cos A
=cos A+tan A-cos A
=tan A

2006-10-30 12:42:13 補充：
0 0,cos B 0, tan B 0π/2 0, cos B 03π/2 0, tan B

2006-10-30 12:42:41 補充：
If A is an acute anglesin (π/2士A)=cos Acos (π/2士A)=干sin Atan (π/2-A)=干cot A (which equals to 1/tan A)sin (π士A)=干sin Acos (π士A)=-cos Atan (π士A)=士tan Asin (3π/2士A)=-cos Acos (3π/2士A)=士sin Atan (3π/2士A)=干cot Asin (2π士A)=士sin Acos (2π士A)=cos Atan (2π士A)=士tan A

cos(3π/2 + A)/tan(A - π) + 1/tan(π/2 - A) - cos(A - 2π)
= -sinA/tanA + 1/(1/tanA) - cosA
= -sinA(cosA/sinA) + tanA - cosA
= tanA - 2cosA

Facts to remember：-π/2, π/2, 3π/2, 5π/2 ---> change sin to cos, cos to sin, tan to 1/tan. -π, π, 2π, 3π ---> no need to change.
Use C.A.S.T to think about the angle is in which quadrant. If cos(X) in C or A, it should be positive sign +cos(X), otherwise it should be negative sign -cos(X). sin(X) and tan(X) also like that.

應該是咁
I think 派 means π
cos(3π/2+A)/tan (A-π)+1/tan(π/2-A)-cos (A-2π)
=sin A/tan[2π-(π-A)]+tan A-cos[2π-(2π-A)]
=sin A/tan (π+A)+tan A-cos A
=sin A/tan A+tan A-cos A
=cos A+tan A-cos A
=tan A
希望幫到你 求你選我最佳答案
求下你
唔該!!!!!!
唔該!!!!!!

2006-10-30 12:36:59 補充：
派 means π是唔是??_?