I started reviewing linear algebra, from a different textbook (Axler's), after taking a fast paced summer class. Unfortunately, I've become conf...

Subtracting $30$ percent of which number leads to $2000$? $$x - (30 \text{ percent of }x) = 2000$$ for example: $$4000 - (50\text{ percent of }4000) = 2000$$

How can I write the function below $$f(x)=\left\{\begin{array}{ll} 1, & 0\leq t\leq 1, \\ 0, & t>1 \end{array}\right.$$ using the unit step fun...

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...

I'm a simple man living my every day life and have not much understanding of math or science. Today I read an article where someone claimed they can ...

I have an exercise that is stated: What's amortized time of series on $n$ operations where all union operations precede find operations? I know it sh...

Using the product i would like to understand if it is possible to determine relationship between two vectors,let us consider the following problem: Vector...

The formula for computing a k-combination with repetitions from n elements is: $$\binom{n + k - 1}{k} = \binom{n + k - 1}{n - 1}$$ I would like if someone...

Lets say there is 40% chance that an event will happen. Than it is said that the probability of the event is increased by five times. I do realize that th...

What is the appropriate usage of the congruent ($\cong$) vs. the approximately ($\approx$) symbols?