User ryang - Mathematics Stack Exchange

29 votes

What is wrong with the following u-substitution?

answered Nov 13, 2017 at 16:18

22 votes

Accepted

Extra solutions when solving $\sin\theta+\cos\theta=\sqrt{2\sin2\theta}$

answered Sep 27, 2021 at 15:25

22 votes

Accepted

Is this alternative proof that $\sqrt 2$ is irrational sound?

answered Jun 15, 2022 at 13:47

18 votes

Accepted

If $x = 1$, then $x + 1 = 5$. Is it a logical proposition?

answered Aug 24, 2021 at 16:14

15 votes

Accepted

Formal logical form of mathematical induction

answered Sep 27, 2024 at 8:44

13 votes

Accepted

How can I avoid the wrong solution when squaring both sides of an equation?

answered Jul 24, 2022 at 14:08

12 votes

Accepted

Using "implies" to refer to material conditional

answered Oct 28, 2020 at 15:41

11 votes

Accepted

What does disjunct mean?

answered Feb 21, 2023 at 9:18

10 votes

Accepted

The average of 10 scores is $25,$ and the lowest score is $20.$ So, the highest score must be...

answered Apr 9, 2023 at 12:41

10 votes

Accepted

Learning to translate natural-language phrases to formal logic

answered May 28, 2022 at 7:21

10 votes

Accepted

Why $x^0=\frac{\pi x}{180}c$?

answered Jul 6, 2021 at 4:19

10 votes

Associativity of logical connectives

answered Sep 26, 2021 at 8:37

10 votes

Why do we assume that this quadratic has one solution?

answered Aug 15, 2021 at 11:53

10 votes

Solving $\sqrt{x+4}-2 =x$ for $x ≠ 0$.

answered Oct 29, 2021 at 16:09

10 votes

The meaning of an implication with the existential quantifier

answered Sep 13, 2024 at 3:54

10 votes

Accepted

Are there different conventions for 'rounding to even'?

answered Aug 27, 2024 at 4:02

9 votes

If instantaneous rates of change aren't that rigorous, how correct is the usage of instantaneous rates of change (like velocity) by physicists?

answered Oct 7, 2021 at 16:44

9 votes

Definition of setting the integration constant equal to zero.

answered Mar 4, 2022 at 4:34

9 votes

Why are the derivatives of complementary angles negative?

answered Apr 24, 2023 at 16:42

9 votes

When is it valid to convert "$\le$" or "$\ge$" to "$=$"?

answered Feb 13, 2023 at 10:47

9 votes

How to remember differentiation formula for logarithmic functions

answered Feb 3, 2023 at 16:07

8 votes

Accepted

Simplifying the surd $\sqrt{3 - \sqrt{8}}$

answered Feb 6, 2023 at 4:45

8 votes

Understanding Universal Quantifiers (Order Matters)

answered Feb 21, 2023 at 4:12

8 votes

Accepted

When proving several statements are equivalent, are we allowed to refer to a previous proved statement?

answered Jul 18, 2022 at 8:40

8 votes

Accepted

Can "that dog is a mammal" be considered a tautology?

answered Aug 7, 2022 at 12:12

8 votes

Accepted

How was Ax + By + Cz + D = 0, an equation for a plane in 3D, "derived"?

answered Mar 11, 2022 at 2:45

8 votes

Accepted

Is a degree measurement a real number?

answered Oct 28, 2021 at 4:51

8 votes

How to interpret "let" in mathematics?

answered Mar 8, 2021 at 2:15

8 votes

Negating quantifiers or statements

answered Sep 23, 2024 at 8:46

7 votes

Understanding the logic of "unique existence" proofs

answered Nov 4, 2024 at 10:20

Stack Exchange Network

1,448 Answers

What is wrong with the following u-substitution?

Extra solutions when solving $\sin\theta+\cos\theta=\sqrt{2\sin2\theta}$

Is this alternative proof that $\sqrt 2$ is irrational sound?

If $x = 1$, then $x + 1 = 5$. Is it a logical proposition?

Formal logical form of mathematical induction

How can I avoid the wrong solution when squaring both sides of an equation?

Using "implies" to refer to material conditional

What does disjunct mean?

The average of 10 scores is $25,$ and the lowest score is $20.$ So, the highest score must be...

Learning to translate natural-language phrases to formal logic

Why $x^0=\frac{\pi x}{180}c$?

Associativity of logical connectives

Why do we assume that this quadratic has one solution?

Solving $\sqrt{x+4}-2 =x$ for $x ≠ 0$.

The meaning of an implication with the existential quantifier

Are there different conventions for 'rounding to even'?

If instantaneous rates of change aren't that rigorous, how correct is the usage of instantaneous rates of change (like velocity) by physicists?

Definition of setting the integration constant equal to zero.

Why are the derivatives of complementary angles negative?

When is it valid to convert "$\le$" or "$\ge$" to "$=$"?

How to remember differentiation formula for logarithmic functions

Simplifying the surd $\sqrt{3 - \sqrt{8}}$

Understanding Universal Quantifiers (Order Matters)

When proving several statements are equivalent, are we allowed to refer to a previous proved statement?

Can "that dog is a mammal" be considered a tautology?

How was Ax + By + Cz + D = 0, an equation for a plane in 3D, "derived"?

Is a degree measurement a real number?

How to interpret "let" in mathematics?

Negating quantifiers or statements

Understanding the logic of "unique existence" proofs