Math inverse

The negate function makes it possible to obtain the additive inverse of a number. How about adding a similar function, but for multiplicative inverse?

// inverse :: Number -> Number

inverse(10); //=> 0.1

[dmitriz]

Mathematically I am familiar with the “inverse” of functions f^-1(f(x)) = x and matrices too. So I would not like naming x => 1 / x “inverse”.

Both are inverses for different group operations. First for the composition of invertible functions, and second for the multiplication.

Which becomes a problem if inverse is used without clearly specifying the operation. reciprocal would be unambiguous.

0 * inverse(0) does not equal 1.

That is because JS forcefully extends the division breaking the maths law: (1/0)*0 != 1 Still formally (a/b)*b == a holds for all valid expressions, but we cannot expect it to hold for the invalid ones.

For Linear Algebra and vector calculus I’d rather pick a specialized library than Ramda…

… and a different language than JavaScript

That language is called maths 😉

[buzzdecafe]

in that case, reciprocal = R.divide(1);