Let . Three students suggest the following domain restrictions to make invertible: A:…

MATHEMATICS · Subjective · CBSE · Mathematics · Relations and Functions · Relations and Functions

Problem

Let q(x)=2x2+8x+5q(x)=2x^{2}+8x+5. Three students suggest the following domain restrictions to make qq invertible: A: x≥−2x\ge -2  B: x≤−2x\le -2  C: −5≤x≤1-5\le x\le 1. Answer the questions below. (i) For each proposed restriction, determine whether it actually makes qq a bijection. Give a clear justification. (ii) Obtain the inverse function corresponding to every valid restriction identified in part (i). (iii) Among the valid restrictions, identify which one produces the largest possible range. Prove that no other interval contained in R\mathbb R yields a larger range for an invertible branch of qq.

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