If roots of x^2 + ax + b = 0 are tan 30° and tan 15°, f... – Algebra

Algebrahard · Past Paper

If roots of x^2 + ax + b = 0 are tan 30° and tan 15°, find 2 + b - a.

✓ Correct Answer: A — 3

tan(30+15) = (tan30+tan15)/(1-tan30tan15) → tan45 = -a/(1-b) → 1 = -a/(1-b) → 1-b = -a → b-a = 1. 2+1=3.

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