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[✓] Substitute a - z == y into an equation?

GROUPS:

Hello, I was wondering with the following equation:

a^4 - 4 a^3 z + 6 a^2 z^2 - 4 a z^3 + z^4

how can I substitute:

a - z == y

to get:

y^4

Thanks

POSTED BY: Stephan Foley
Answer
19 days ago
a^4 - 4 a^3 z + 6 a^2 z^2 - 4 a z^3 + z^4
% /. a -> y + z // Simplify
POSTED BY: David J M Park Jr
Answer
19 days ago

very nice, works like a charm...thanks for the reply!

POSTED BY: Stephan Foley
Answer
19 days ago

Sometimes giving Simplify the optional second argument, which are the assumptions that you are telling Simplify that it can depend on always being true and which it is free to make use of as it sees fit, can accomplish interesting and helpful things.

Simplify[a^4 - 4 a^3 z + 6 a^2 z^2 - 4 a z^3 + z^4, a - z == y]

immediately returns

y^4
POSTED BY: Bill Simpson
Answer
19 days ago

Group Abstract Group Abstract