Proving collinearity in acute triangle altitude feet and reflection

[Vishalrox]

I need help in this ques !

ABC is acute triangle. A1, B1, C1 are foot of altitudes. A1 is reflected about AC to get A2. Prove that B1, C1, A2 are collinear...i couldn't evn figure out how to solve it...but i need it just tell me the method no need to proove...or just tell me the idea how to proove...i need it...plez don't remove this ques...

I tried with the method of Angle chase geometry..but still couldn't get...

 

[Eynstone]

Try using complex numbers or coordinate geometry.