[Closed] How can I calculate this?

I’m trying to collapse 2 positions XYZ one on top of the other without baking all the transform.
getting the final transformation value and applying the resulting value is easy but I have some issue regarding how should I collapse the tangents.

How can I add those 2 tracks

and

in order to get

(I used the animation layer collapse to get the pictures)

Should I just transpose the tangents value? Is there a mathematic formula for this?
after some research it seems like all I need to do is to transpose the tangents value before an after… Am I correct?