Simplify: Sin2x/1-Cos2x

To simplify the expression (sin2x)/(1 - cos2x), we can use the trigonometric identity:

sin^2(x) + cos^2(x) = 1

First, let's write sin^2(2x) as (sin(2x))^2:

(sin(2x))^2 / (1 - cos(2x))

Now, we can use another trigonometric identity:

sin(2x) = 2sin(x)cos(x)

Replacing sin(2x) with 2sin(x)cos(x):

(2sin(x)cos(x))^2 / (1 - cos(2x))

Expanding (2sin(x)cos(x))^2:

4sin^2(x)cos^2(x) / (1 - cos(2x))

Now, we can use the Pythagorean identity sin^2(x) + cos^2(x) = 1 to replace sin^2(x) and cos^2(x):

4(1 - cos^2(x))(cos^2(x)) / (1 - cos(2x))

Multiplying out the numerator:

4cos^2(x) - 4cos^4(x) / (1 - cos(2x))

Now, we can distribute the negative sign in the numerator:

4cos^2(x) - 4cos^4(x) / (1 - cos(2x))

Finally, we have simplified the expression:

4cos^2(x) - 4cos^4(x) / (1 - cos(2x))