Hello, I need help on my Mathematics 30-1 Quiz 7.1 (Pre-calculus) Question #17-#18

Quiz 7.1 - TS 17. An expression equivalent to sin 0 + cot 0 cos 0 is A. 1 B. csc 0 C sec 0 D. cot2 0 Hint: Simplify using reciprocal trigonometric identities. 18. The restrictions on the variable for the expression , _ are A. 07 6 1 + 2TEN, 6 5TE + 2TN, nT, n E I + 1 + 2 TCM, B. 076 11T + 2Tn, . 2 + nn, n E I Iftun C. 0+ +2TM, 3 4TC + 2TIM, 2 1 + nn, n E I D. 07 6 5TE + 2TEN, 6 7 TC + 2 TEN, 7 + ni, n E I Hint: The denominator cannot be equal to zero