If the incircle of triangle passes through its circumcentre

MATHEMATICS · Single correct · A Level · Mathematics · Trigonometry · Trigonometry

Problem

If the incircle of triangle

ABC

passes through its circumcentre, then

\cos A+\cos B+\cos C

is (1)

-2

(2)

\sqrt{2}

(3)

-\sqrt{2}

(4) None of these