Ambiguous Cases of Sine Rule

Ambiguous Cases of Sine Rule

Secondary 3
  1. \(\,\)A set of information that will give \(2\) sets of solutions is considered ambiguous.
  2. \(\,\)Ambiguous cases when solving a triangle arise because sine ratio of an ACUTE or OBTUSE angle are both positive.
  3. Let \(a\) and \(b\) be opposite \(A\) and \(B\). For acute \(A\), exactly two triangles occur when \(b\sin A<a<b\). The condition \(a<b\) alone is insufficient: check the sine range, both supplementary candidates for \(B\), and \(A+B<180^\circ\).

Draw the possible triangles \(ABC\), where \(a=\sqrt{29}\approx5.39\) units, \(b=\sqrt{50}\approx7.07\) units and angle \(BAC=45{}^\circ \) .

Video Solution:

Video Solution

Video solution locked

A free account saves your progress; this video needs a course plan.

Solution:

Solution locked

680+ questions here come with free worked solutions. A free account saves your questions and progress; this one needs a course plan.

Answer:\((B,C,c)=(68.2^\circ,66.8^\circ,7\text{ units})\) or \((111.8^\circ,23.2^\circ,3\text{ units})\)

Need help? Join our E-Maths tuition for O-Level success.

Learn more