化简式子 证明等式化简1.cos(90+a)+sin(180-a)-sin(180+a)-sin(-a)证明1.sin(a+b)/cosacosb=tana+tanb2.sin(a+b)cos(a-b)=sinacosa+sinbcosb
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![化简式子 证明等式化简1.cos(90+a)+sin(180-a)-sin(180+a)-sin(-a)证明1.sin(a+b)/cosacosb=tana+tanb2.sin(a+b)cos(a-b)=sinacosa+sinbcosb](/uploads/image/z/11516492-20-2.jpg?t=%E5%8C%96%E7%AE%80%E5%BC%8F%E5%AD%90+%E8%AF%81%E6%98%8E%E7%AD%89%E5%BC%8F%E5%8C%96%E7%AE%801.cos%2890%2Ba%29%2Bsin%28180-a%29-sin%28180%2Ba%29-sin%28-a%29%E8%AF%81%E6%98%8E1%EF%BC%8Esin%28a%2Bb%29%2Fcosacosb%3Dtana%2Btanb2.sin%28a%2Bb%29cos%28a-b%29%3Dsinacosa%2Bsinbcosb)
化简式子 证明等式化简1.cos(90+a)+sin(180-a)-sin(180+a)-sin(-a)证明1.sin(a+b)/cosacosb=tana+tanb2.sin(a+b)cos(a-b)=sinacosa+sinbcosb
化简式子 证明等式
化简
1.cos(90+a)+sin(180-a)-sin(180+a)-sin(-a)
证明
1.sin(a+b)/cosacosb=tana+tanb
2.sin(a+b)cos(a-b)=sinacosa+sinbcosb
化简式子 证明等式化简1.cos(90+a)+sin(180-a)-sin(180+a)-sin(-a)证明1.sin(a+b)/cosacosb=tana+tanb2.sin(a+b)cos(a-b)=sinacosa+sinbcosb
化简
-sin a+sin a-(-sin a)-(-sin a)
=2sin a
证明
1.原式=sin a*cos b+cos a*sin b/cos a*cos b
分子分母同除以cos a*cos b
=tan a+tan b
2.原式=(sin a*cos b+cos a*sin b)(cos a*coa b+sin a*sin b)
将式子乘开后合并同类项
=sin a*cos a+sin b*cos b
cos(90+a)+sin(180-a)-sin(180+a)-sin(-a)=-sin(a)+2*sin(a)+sin(a)=2*sin(a)
sin(a+b)/cosacosb=(sinacosb+cosasinb)/cosacosb=tana+tanb
2sin(a+b)cos(a-b)=sin(2a)+sin(2b)=2sinacosa+2sinbcosb
sin(a+b)cos(a-b)=sinacosa+sinbcosb