Carefully go through the steps of the proof below. Then answer the questions at the end. Claim. The square of an odd num
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Carefully go through the steps of the proof below. Then answer the questions at the end. Claim. The square of an odd num
questions at the end. Claim. The square of an odd number is odd. Proof. (1) u EZ and u is odd (2) u = 2k + 1 ; by ; by ; by ; by ; by (6) u² ; by (7) u² is odd ; by (8) u Z and u is odd ⇒ u² is odd ; by (9) Vx [x = Z and x is odd ⇒ x² is odd] ; by (1) Decide whether this is: (i) direct proof (ii) proof by contraposition - (iii) proof by contradiction (iv) proof by cases. (2) Decide whether the proof is correct or not. (2a) If the proof is incorrect, identify the first line where a mistake happens. (2b) If the proof is correct, fill in the blanks by choosing from the following list: (i) by algebra - (ii) by assumption - (iii) by closure - (iv) by definition - (v) by definition, for some suitable choice of k (when you enter your answers on Brightspace, you may use the abbreviated form in boldface) - (vi) by logic. [2P] (3) (2k + 1)² (4) u² = 4k² + 4k+1 (5) - u² = 2(2k² + 2k) + 1 2 u arbitrary = 2m + 1, for m = 2k² + 2k
Carefully go through the steps of the proof below. Then answer the