解答
tan(2x+13)=cot(x+53∘)
解答
x=12.33333…∘−313+3360∘n,x=72.33333…∘−313+3360∘n
+1
弧度
x=54037π−313+32πn,x=540217π−313+32πn求解步骤
tan(2x+13)=cot(x+53∘)
两边减去 cot(x+53∘)tan(2x+13)−cot(x+53∘)=0
用 sin, cos 表示
−cot(53∘+x)+tan(13+2x)
使用基本三角恒等式: cot(x)=sin(x)cos(x)=−sin(53∘+x)cos(53∘+x)+tan(13+2x)
使用基本三角恒等式: tan(x)=cos(x)sin(x)=−sin(53∘+x)cos(53∘+x)+cos(13+2x)sin(13+2x)
化简 −sin(53∘+x)cos(53∘+x)+cos(13+2x)sin(13+2x):sin(180180x+9540∘)cos(2x+13)−cos(1809540∘+180x)cos(2x+13)+sin(13+2x)sin(180180x+9540∘)
−sin(53∘+x)cos(53∘+x)+cos(13+2x)sin(13+2x)
sin(53∘+x)cos(53∘+x)=sin(1809540∘+180x)cos(1809540∘+180x)
sin(53∘+x)cos(53∘+x)
化简 53∘+x:1809540∘+180x
53∘+x
将项转换为分式: x=180x180=53∘+180x⋅180
因为分母相等,所以合并分式: ca±cb=ca±b=1809540∘+x⋅180
=sin(1809540∘+x⋅180)cos(53∘+x)
化简 53∘+x:1809540∘+180x
53∘+x
将项转换为分式: x=180x180=53∘+180x⋅180
因为分母相等,所以合并分式: ca±cb=ca±b=1809540∘+x⋅180
=sin(1809540∘+x⋅180)cos(1809540∘+x⋅180)
=−sin(180180x+9540∘)cos(180180x+9540∘)+cos(2x+13)sin(2x+13)
sin(1809540∘+x180),cos(13+2x)的最小公倍数:sin(180180x+9540∘)cos(2x+13)
sin(1809540∘+x⋅180),cos(13+2x)
最小公倍数 (LCM)
计算出由出现在 sin(1809540∘+x180) 或 cos(13+2x)中的因子组成的表达式=sin(180180x+9540∘)cos(2x+13)
根据最小公倍数调整分式
将每个分子乘以其分母转变为最小公倍数所要乘以的同一数值 sin(180180x+9540∘)cos(2x+13)
对于 sin(1809540∘+x⋅180)cos(1809540∘+x⋅180):将分母和分子乘以 cos(2x+13)sin(1809540∘+x⋅180)cos(1809540∘+x⋅180)=sin(1809540∘+x⋅180)cos(2x+13)cos(1809540∘+x⋅180)cos(2x+13)
对于 cos(13+2x)sin(13+2x):将分母和分子乘以 sin(180180x+9540∘)cos(13+2x)sin(13+2x)=cos(13+2x)sin(180180x+9540∘)sin(13+2x)sin(180180x+9540∘)
=−sin(1809540∘+x⋅180)cos(2x+13)cos(1809540∘+x⋅180)cos(2x+13)+cos(13+2x)sin(180180x+9540∘)sin(13+2x)sin(180180x+9540∘)
因为分母相等,所以合并分式: ca±cb=ca±b=sin(180180x+9540∘)cos(2x+13)−cos(1809540∘+x⋅180)cos(2x+13)+sin(13+2x)sin(180180x+9540∘)
=sin(180180x+9540∘)cos(2x+13)−cos(1809540∘+180x)cos(2x+13)+sin(13+2x)sin(180180x+9540∘)
cos(13+2x)sin(180180x+9540∘)−cos(13+2x)cos(180180x+9540∘)+sin(13+2x)sin(180180x+9540∘)=0
g(x)f(x)=0⇒f(x)=0−cos(13+2x)cos(180180x+9540∘)+sin(13+2x)sin(180180x+9540∘)=0
使用三角恒等式改写
−cos(13+2x)cos(180180x+9540∘)+sin(13+2x)sin(180180x+9540∘)
使用角和恒等式: cos(s)cos(t)−sin(s)sin(t)=cos(s+t)−cos(s)cos(t)+sin(s)sin(t)=−cos(s+t)=−cos(13+2x+180180x+9540∘)
−cos(13+2x+180180x+9540∘)=0
两边除以 −1
−cos(13+2x+180180x+9540∘)=0
两边除以 −1−1−cos(13+2x+180180x+9540∘)=−10
化简cos(13+2x+180180x+9540∘)=0
cos(13+2x+180180x+9540∘)=0
cos(13+2x+180180x+9540∘)=0的通解
cos(x) 周期表(周期为 360∘n):
x030∘45∘60∘90∘120∘135∘150∘cos(x)12322210−21−22−23x180∘210∘225∘240∘270∘300∘315∘330∘cos(x)−1−23−22−210212223
13+2x+180180x+9540∘=90∘+360∘n,13+2x+180180x+9540∘=270∘+360∘n
13+2x+180180x+9540∘=90∘+360∘n,13+2x+180180x+9540∘=270∘+360∘n
解 13+2x+180180x+9540∘=90∘+360∘n:x=12.33333…∘−313+3360∘n
13+2x+180180x+9540∘=90∘+360∘n
将 13到右边
13+2x+180180x+9540∘=90∘+360∘n
两边减去 1313+2x+180180x+9540∘−13=90∘+360∘n−13
化简2x+180180x+9540∘=90∘+360∘n−13
2x+180180x+9540∘=90∘+360∘n−13
在两边乘以 180
2x+180180x+9540∘=90∘+360∘n−13
在两边乘以 1802x⋅180+180180x+9540∘⋅180=90∘⋅180+360∘n⋅180−13⋅180
化简
2x⋅180+180180x+9540∘⋅180=90∘⋅180+360∘n⋅180−13⋅180
化简 2x⋅180:360x
2x⋅180
数字相乘:2⋅180=360=360x
化简 180180x+9540∘⋅180:180x+9540∘
180180x+9540∘⋅180
分式相乘: a⋅cb=ca⋅b=180(180x+9540∘)⋅180
约分:180=180x+9540∘
化简 90∘⋅180:16200∘
90∘⋅180
分式相乘: a⋅cb=ca⋅b=16200∘
数字相除:2180=90=16200∘
化简 360∘n⋅180:64800∘n
360∘n⋅180
数字相乘:2⋅180=360=64800∘n
化简 −13⋅180:−2340
−13⋅180
数字相乘:13⋅180=2340=−2340
360x+180x+9540∘=16200∘+64800∘n−2340
540x+9540∘=16200∘+64800∘n−2340
540x+9540∘=16200∘+64800∘n−2340
540x+9540∘=16200∘+64800∘n−2340
将 9540∘到右边
540x+9540∘=16200∘+64800∘n−2340
两边减去 9540∘540x+9540∘−9540∘=16200∘+64800∘n−2340−9540∘
化简540x=6660∘+64800∘n−2340
540x=6660∘+64800∘n−2340
两边除以 540
540x=6660∘+64800∘n−2340
两边除以 540540540x=12.33333…∘+54064800∘n−5402340
化简
540540x=12.33333…∘+54064800∘n−5402340
化简 540540x:x
540540x
数字相除:540540=1=x
化简 12.33333…∘+54064800∘n−5402340:12.33333…∘−313+3360∘n
12.33333…∘+54064800∘n−5402340
对同类项分组=12.33333…∘−5402340+54064800∘n
消掉 5402340:313
5402340
约分:180=313
=12.33333…∘−313+54064800∘n
消掉 54064800∘n:3360∘n
54064800∘n
约分:180=3360∘n
=12.33333…∘−313+3360∘n
x=12.33333…∘−313+3360∘n
x=12.33333…∘−313+3360∘n
x=12.33333…∘−313+3360∘n
解 13+2x+180180x+9540∘=270∘+360∘n:x=72.33333…∘−313+3360∘n
13+2x+180180x+9540∘=270∘+360∘n
将 13到右边
13+2x+180180x+9540∘=270∘+360∘n
两边减去 1313+2x+180180x+9540∘−13=270∘+360∘n−13
化简2x+180180x+9540∘=270∘+360∘n−13
2x+180180x+9540∘=270∘+360∘n−13
在两边乘以 180
2x+180180x+9540∘=270∘+360∘n−13
在两边乘以 1802x⋅180+180180x+9540∘⋅180=270∘⋅180+360∘n⋅180−13⋅180
化简
2x⋅180+180180x+9540∘⋅180=270∘⋅180+360∘n⋅180−13⋅180
化简 2x⋅180:360x
2x⋅180
数字相乘:2⋅180=360=360x
化简 180180x+9540∘⋅180:180x+9540∘
180180x+9540∘⋅180
分式相乘: a⋅cb=ca⋅b=180(180x+9540∘)⋅180
约分:180=180x+9540∘
化简 270∘⋅180:48600∘
270∘⋅180
分式相乘: a⋅cb=ca⋅b=48600∘
数字相乘:3⋅180=540=48600∘
数字相除:2540=270=48600∘
化简 360∘n⋅180:64800∘n
360∘n⋅180
数字相乘:2⋅180=360=64800∘n
化简 −13⋅180:−2340
−13⋅180
数字相乘:13⋅180=2340=−2340
360x+180x+9540∘=48600∘+64800∘n−2340
540x+9540∘=48600∘+64800∘n−2340
540x+9540∘=48600∘+64800∘n−2340
540x+9540∘=48600∘+64800∘n−2340
将 9540∘到右边
540x+9540∘=48600∘+64800∘n−2340
两边减去 9540∘540x+9540∘−9540∘=48600∘+64800∘n−2340−9540∘
化简540x=39060∘+64800∘n−2340
540x=39060∘+64800∘n−2340
两边除以 540
540x=39060∘+64800∘n−2340
两边除以 540540540x=72.33333…∘+54064800∘n−5402340
化简
540540x=72.33333…∘+54064800∘n−5402340
化简 540540x:x
540540x
数字相除:540540=1=x
化简 72.33333…∘+54064800∘n−5402340:72.33333…∘−313+3360∘n
72.33333…∘+54064800∘n−5402340
对同类项分组=72.33333…∘−5402340+54064800∘n
消掉 5402340:313
5402340
约分:180=313
=72.33333…∘−313+54064800∘n
消掉 54064800∘n:3360∘n
54064800∘n
约分:180=3360∘n
=72.33333…∘−313+3360∘n
x=72.33333…∘−313+3360∘n
x=72.33333…∘−313+3360∘n
x=72.33333…∘−313+3360∘n
x=12.33333…∘−313+3360∘n,x=72.33333…∘−313+3360∘n