Question

In a triangle \(ABC\), if \[ a=\sqrt3+1,\qquad b=\sqrt3-1 \] and \[ \angle C=60^\circ, \] then \(\cos(A-B)=\)

• A. \(\dfrac{\sqrt3+1}{2\sqrt2}\)
• B. \(\dfrac{2}{\sqrt3}\)
• C. \(0\)
• D. \(1\)

Hint:

For questions involving sides and included angle, first use the cosine rule to determine the third side. Then apply the sine rule or angle identities to evaluate the required trigonometric expression.

Answer 1

The Correct Option is C