Metamath Proof Explorer


Theorem affineid

Description: Identity of an affine combination. (Contributed by AV, 2-Feb-2023)

Ref Expression
Hypotheses affineid.f φ A
affineid.x φ T
Assertion affineid φ 1 T A + T A = A

Proof

Step Hyp Ref Expression
1 affineid.f φ A
2 affineid.x φ T
3 1cnd φ 1
4 3 2 1 subdird φ 1 T A = 1 A T A
5 1 mulid2d φ 1 A = A
6 5 oveq1d φ 1 A T A = A T A
7 4 6 eqtrd φ 1 T A = A T A
8 7 oveq1d φ 1 T A + T A = A - T A + T A
9 2 1 mulcld φ T A
10 1 9 npcand φ A - T A + T A = A
11 8 10 eqtrd φ 1 T A + T A = A