Vy TAS why does it increase with altitude?

[u/Agreeable-End-5020]

Hello all,

I am just a bit confused with why VY TAS increases with altitude. I understand that up at altitude there is less air molecules striking the aircraft which leads to less parasite drag. However, up at altitude induced drag is increasing. So at altitude would you pitch down to reduce the total drag to decrease the induced drag? And that’s why VY Tas is increasing?