411 REFERENCE · Wikibooks
Linear Algebra and the C Language/a08z
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
__NOTOC__
A change of basis consists of converting every assertion expressed in terms of coordinates relative to one basis into an assertion expressed in terms of coordinates relative to the other basis... Wikipedia: Change of basis
Change of basis with invertible matrices:
Let B, the matrix for the change of basis for the basis B
a) Find the coordinates of U in standard basis:
B * U_b = U_s (*)
b) Find the coordinates of U in basis B:
U_b = invB U_s
We have: B * U_b = U_s (*)
Let's use the inverse of B: invB B * U_b = invB U_s
ID * U_b = invB U_s
We have U in basis B: U_b = invB U_s
Exemples d'applications :
+ a) Example b) Example
Change of basis with non-invertible matrices:
Let B, the matrix for the change of basis for the basis B
a) Find the coordinates of U in standard basis:
B U_b = U_s (*)
b) Find the coordinates of U in basis B:
You must create the system and resolve it:
You have (*): B U_b = U_s (B: non-invertible matrix)
You must resolve the system: B|U_s (Give U in base b: U_b)
Exemples d'applications :
+ a) Example b) Example