1) cscθsinθ-sin^2θ

2)sinθcscθ/tanθ

3)secθ/cotθ+tanθ

4)(1-cosθ)(1+cosθ)

Is there a question ?

how do you solve them

1) To simplify the expression cscθsinθ - sin^2θ, we can first use the identity cscθ = 1/sinθ.

So, the expression becomes (1/sinθ)sinθ - sin^2θ.

Now, we can simplify further by canceling out the sinθ terms, giving us 1 - sin^2θ.

Lastly, we can use the trigonometric identity sin^2θ + cos^2θ = 1.

Substituting this identity into our expression, we get 1 - (1 - cos^2θ).

Simplifying this expression, we have 1 - 1 + cos^2θ, which simplifies to cos^2θ.

Therefore, the simplified expression is cos^2θ.

2) To simplify the expression sinθcscθ/tanθ, we can first use the identity cscθ = 1/sinθ.

So, the expression becomes sinθ * (1/sinθ) / tanθ.

Next, we can cancel out the sinθ terms, giving us 1 / tanθ.

Lastly, we can use the trigonometric identity tanθ = sinθ/cosθ.

Substituting this identity into our expression, we get 1 / (sinθ/cosθ).

To divide by a fraction, we can multiply by the reciprocal of that fraction.

Therefore, our expression simplifies to cosθ.

3) To simplify the expression secθ / (cotθ + tanθ), we can first use the identity secθ = 1/cosθ and cotθ = 1/tanθ.

So, the expression becomes (1/cosθ) / (1/tanθ + tanθ).

Next, we can simplify further by taking the reciprocal of the denominator, which is equal to tanθ + 1/tanθ.

To simplify this, we can use the trigonometric identity tanθ + 1/tanθ = secθ + cosecθ.

Therefore, our expression simplifies to (1/cosθ) / (secθ + cosecθ).

To divide by a fraction, we can multiply by the reciprocal of that fraction.

So, our expression becomes (1/cosθ) * (1/(secθ + cosecθ)).

Multiplying the numerators and the denominators, we get 1 / (cosθ * (secθ + cosecθ)).

Further simplification isn't possible unless we have additional information about the values of the trigonometric functions.

4) To simplify the expression (1 - cosθ)(1 + cosθ), we can use the identity (a - b)(a + b) = a^2 - b^2.

Applying this identity to our expression, we have (1^2 - cos^2θ).

Since 1^2 = 1, our expression simplifies to 1 - cos^2θ.