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2 csc 2x = cot x + tan x

Show that the left side equals the right side.
You will also have to use the double-angle identity for sin, which is: sin 2A = 2 sin x cos x

 Feb 25, 2016
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Verify the following identity:
2 csc(2 x)  =  cot(x)+tan(x)

Write cotangent as cosine/sine, cosecant as 1/sine and tangent as sine/cosine:
2 1/(sin(2 x))  =  ^?(cos(x))/(sin(x))+(sin(x))/(cos(x))

Put (cos(x))/(sin(x))+(sin(x))/(cos(x)) over the common denominator sin(x) cos(x): (cos(x))/(sin(x))+(sin(x))/(cos(x))  =  (cos(x)^2+sin(x)^2)/(cos(x) sin(x)):
2/(sin(2 x))  =  ^?(cos(x)^2+sin(x)^2)/(cos(x) sin(x))

Cross multiply:
2 cos(x) sin(x)  =  ^?sin(2 x) (cos(x)^2+sin(x)^2)

sin(x)^2 = 1-cos(x)^2:
2 cos(x) sin(x)  =  ^?sin(2 x) (cos(x)^2+1-cos(x)^2)

cos(x)^2+1-cos(x)^2 = 1:
2 cos(x) sin(x)  =  ^?sin(2 x)

sin(2 x) = 2 sin(x) cos(x):
2 cos(x) sin(x)  =  ^?2 cos(x) sin(x)

The left hand side and right hand side are identical:
Answer: | (identity has been verified)

 Feb 25, 2016

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