general

Difference between "Show" and "Prove"

In many mathematics problems you see the phrase "prove that..." or "show that..." something is. What's the difference between these two phrases? Is "...

Published: Aug 29, 2026

updates

The right way of proving LHS = RHS

I'm currently brushing up on my math before heading back to school for my bachelor's and am practicing on some questions. Given the following eq...

Published: Aug 29, 2026

news

What does "with respect to x" mean when integrating?

When dealing with derivatives, "with respect to $x$" means we are observing how a small change in $x$ (the input) affects a change in $y$ (the o...

Published: Aug 29, 2026

general

How to find a normal vector on a surface from a point out of the surface?

For example, if we consider a shape in 2D like a circle at center $(x_0,y_0)$ with radius R so the equation would be: $$f(x,y)=(x-x_0)^2+(y-y_0)^2-R^2$$ n...

Published: Aug 29, 2026

updates

Find the least nonnegative residue

Find the least nonnegative residue of $5^{18} \mod 11$. To do this I took $5^2 \equiv 3 \mod 11$. Then I did $(5^2)^5 \equiv 3^5 \mod 11$. And $3^5 \equiv...

Published: Aug 29, 2026

updates

Determine whether the following statements are true or false, and then prove answers

Determine whether statement is true or false, and then prove answer. For all integers $a,b,c$: a) if $a|bc$ and gcd$(a,b) = 1$ then $a|c$ b) if $a|c$ and ...

Published: Aug 29, 2026

updates

Finding the equation for a line tangent to a parametric curve

I have the parametric equation $x = 2t - 1$ $y = 3t + 5$ $t = -1$ (defined as $t_0$) I am trying to find the line tangent to it. My book says if $x'(...

Published: Aug 29, 2026

general

Difference between horizontal and vertical line tests.

Trying to understand what the differnce is between a vertical and horizontal line test. If an equation fails the vertical line test, what does that tell y...

Published: Aug 29, 2026

updates

Integrating $\sec^2 x$ from first principles

Is it possible to solve $\int \sec^2 x ~dx$ without knowing that $\frac{d}{dx}\tan x = \sec^2 x$?

Published: Aug 29, 2026

general

Preparations for reading Algebraic Number Theory by Serge Lang

I am eager to learn algebraic number theory. It seems that Serge Lang's Algebraic Number Theory is one of the standard introductory texts (correct me...

Published: Aug 29, 2026