Multiple choice

If the roots of the quadratic equation $m{ x }^{ 2 }-nx+k=0$ are $\tan { { 33 }^{ o } } $ and $\tan { { 12 }^{ o } } $, then the value of $\cfrac { 2m+n+k }{ m } $ is equal to

  1. $0$
  2. $1$
  3. $3$
  4. $2$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Roots are tan(33) and tan(12). Sum of roots = n/m = tan(33)+tan(12). Product = k/m = tan(33)tan(12). Using tan(A+B) formula, tan(45) = (tan(33)+tan(12))/(1-tan(33)tan(12)) = 1. So (n/m) = 1 - (k/m), thus n/m + k/m = 1. The expression (2m+n+k)/m = 2 + (n+k)/m = 2 + 1 = 3.

AI explanation

By Vieta's formulas, the sum of the roots is tan(33) + tan(12) = n/m and the product is tan(33) * tan(12) = k/m. Using the tangent addition formula for 45 degrees, we know tan(45) = tan(33 + 12) = (tan(33) + tan(12)) / (1 - tan(33)*tan(12)). Since tan(45) = 1, we have the equation 1 = (n/m) / (1 - k/m), which simplifies to 1 - k/m = n/m, or m - k = n. Substituting n = m - k into the given expression (2m + n + k) / m yields (2m + m - k + k) / m, which equals 3m / m = 3.