数学题sin^(α+π)cos(-α+π)/tan(α+π)tan(α+2π)cos^(-α-π)化简:1.sin^(α+π)cos(-α+π)/tan(α+π)tan(α+2π)cos^(-α-π)计算:1.sin35cos25+sin55cos65 2.cos28cos73+cos62cos17
问题描述:
数学题sin^(α+π)cos(-α+π)/tan(α+π)tan(α+2π)cos^(-α-π)
化简:1.sin^(α+π)cos(-α+π)/tan(α+π)tan(α+2π)cos^(-α-π)
计算:1.sin35cos25+sin55cos65
2.cos28cos73+cos62cos17
答
1.sin35cos25+sin55cos65
=sin35cos25+cos35sin25
=sin(35+25)
=sin60=(根号3)/2
2.cos28cos73+cos62cos17
=cos28sin17+sin28cos17
=sin(28+17)
=sin45
=(根号2)/2