SOLUTION: sin10�cot 20�cos 30�tan40�tan50�cosec 60�cot70�sec 80�=1 prove.

Question 1078890: sin10�cot 20�cos 30�tan40�tan50�cosec 60�cot70�sec 80�=1 prove.
Answer by ikleyn(52873) (Show Source): You can put this solution on YOUR website!
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sin10�cot 20�cos 30�tan40�tan50�cosec 60�cot70�sec 80�=1 prove.
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Use basic trigonometry identities:

1.  sin(10�) = cos(80�) =    --->  sin(10�)*sec(80�) = 1.


2.  cot(20�) =    --->  cot(20�)*cot(70�) = 1.


3.  cos(30�) = sin(60�) =    --->  cos(30�)*cosec(60�) = 1.


4.  tan(40�) =    --->  tan(40�)*tan(50�) = 1.



5.  =======>  sin10�cot 20�cos 30�tan40�tan50�cosec 60�cot70�sec 80� = 1.   Proved.

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