Trig Identity.

Identity? Where is the equal sign?

It has to be solved on its own.

To simplify the given trigonometric expression, we can use the identity:

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

Now, let's substitute this identity into the expression:

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

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

Next, we can factor out a common term in the denominator:

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

Now, we can simplify further by using another trigonometric identity:

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

Substituting this identity into the expression:

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

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

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

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

Finally, since sin^2(x) / sin^2(x) = 1, we have:

1/(sin^2(x))

Therefore, the simplified form of the given trigonometric expression is 1/(sin^2(x)).