Question

If ABCD is a cyclic quadrilateral then cos A+cos B+cos C+cos D=0

Answer 1

Answer:

0

Step-by-step explanation:

We know that the opposite angles of a cyclic quadrilateral are supplementary,

i.e., A+C=π and B+D=π.

Therefore,

A=π−C and B=π−D

⇒ cosA=cos(π−C)=−cosC

and cosB=cos(π−D)=−cosD

∴ cosA + cosB + cosC + cosD =

−cosC − cosD + cosC + cosD = 0

Answered by GauthMath.

Answer 2

If ABCD is a cyclic quadrilateral then cos A+cos B+cos C+cos D=