∴√3sinbcosa+Sina cosc+sinc Sina cosa = 0

√3sinBcosA + sin？ AcosC + sinCsinAcosA=0

Mobile project:

Sin? AcosC + sinCsinAcosA=-√3sinBcosA

SiNa extract common factor:

sinA(sinA cosc+sinc cosa)=-√3 sinb cosa

Two angle sum formula:

Sina? sin(A+C)=-√3sinBcosA

In △ABC: A+C = π-B。

Sina? sin(π-B)=-√3sinBcosA

Inductive formula: sinAsinB=-√3sinBcosA

∫∠B is the inner angle in △ABC.

∴sinB≠0

SINB points on both sides: SINA =-√ 3cosa.

Divide both sides by COSA: TANA =-√ 3.