Simply (cotθ-cscθ) ^2

[ (cosθ-1) ^2] / (sinθ) ^2

Step-by-step explanation:

(cotθ-cscθ) ^2

(cotθ) ^2-2cscθcotθ + (cscθ) ^2

(cosθ/sinθ) ^2-2 (cosθ / (sinθ) ^2) + 1 / (sinθ) ^2

All have same denominator, (sinθ) 2, add/subtract

((cosθ) ^2-2cosθ+1) / (sinθ) ^2

Factor the top

[ (cosθ-1) ^2] / (sinθ) ^2