化简/π-5/+/4-π/+/-π+3.1/

化简/π-5/+/4-π/+/-π+3.1/ 化简sin(4π-a)*sin(5π-a)=? 化简[sin(π-α)cos(3π-α)tan(-α-π)]/[tan(4π-α)sin(5π+α)] 化简：[tan(5/4)π+tan(5/12)π]/[1-tan(5/12)π] 化简：[tan（5π）/4+tan(5π)/12]/[1-tan(5π)/12] 化简：|π-4|+|3-π| 算出来 sin(-11/6π)+cos12/5π×tan4π化简 化简:(sin(α-3π)*cos(-α))/(tan(α-5π)*cos^2(α-5π)*tan(4π-α)) 化简sin(α-5π)/cos(3π-α)×cos(π/2-α)/sin(α-3π)×cos(8π-α)/sin(-α-4π) 化简[sin(θ-5π)cot(π/2-θ)cos(8π-θ)]/[tan(3π-θ)tan(θ-3/2π)sin(-θ-4π)] sin(θ -5π)/tan(3π-θ)*cot(π/2-θ)/tan(θ -3/2π)*cos(8π-θ)/sin(-θ-4π)化简 化简（-11/6 π)+cos(12/5 π)tan（4π）-1/(cos(13π/3)) tan(α+π/4)化简 化简(tan5π/4+tan5π/12)/(1-tan5π/12)(tan 5π/4 + tan 5π/12)/(1-tan 5π/12) =(tan π/4 + tan π/6+π/4 )/(1-tan π/4*tan π/6+π/4 ) =tan(π/4 + π/6+π/4 )=tan(π/2+π/6) 请问我这样算错在哪呢?tan π/2不是无意义吗? 化简sin(3π-x)cos(x-3/2)cos(4π-x)/tan(x-5π)cos(π/2+x)sin(x-5/2π) 化简sin(3π-x)cos(x-3/2)cos(4π-x)/tan(x-5π)cos(π/2+x)sin(x-5/2π) 化简sin（a-5π）cos（-π/2-a）cos（8π-a）/sin（a-3π/2）sin（-a-4π） 化简sin（a-5π）cos（-π/2-a）cos（8π-a）/sin（a-3π/2）sin（-a-4π）