4 ms·
I can’t believe you are downvoted. In math sqrt is defined as the positive one. It seems HN readers need a refresher.
by zeroonetwothree 4y ago
I can’t believe you are downvoted. In math sqrt is defined as the positive one. It seems HN readers need a refresher.
- BeetleB 4y agoMost people are taught that there are two values for the square root. It was only in later math courses (e.g. precalculus) that they reserved the square root symbol exclusively for the positive square root.
- thaumasiotes 4y agoThat is not what people are taught. If that were true, the numerator in the quadratic equation would be "-b + √(b² - 4ac)", not "-b ± √(b² - 4ac)".
- BeetleB 4y agoYour statement assumes the educational system values consistency, which is a clearly false assumption.
- thaumasiotes 4y agoTextbooks aren't that bad. Here's what Pearson's Algebra 1 says when introducing the novel concept of the radical sign: > The radical symbol √ indicates a nonnegative square root, also called a principal square root. I quoted that one because it's available on libgen ( http://library.lol/main/BE522034F8D3680B248162CD2C35D455 http://library.lol/main/BE522034F8D3680B248162CD2C35D455 , page 16), but obviously every basic algebra textbook covers this. The symbol is never discussed -- or used -- in any other terms than that it uniquely refers to a positive (or zero) square root.
- BeetleB 4y agoYour evidence is consistent with my claims. Or rather: I never claimed there aren't textbooks that define it as the positive square root.
- thaumasiotes 4y agoAll textbooks define it that way. There is no other definition available for that symbol.