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David Quinn
  • Member for 7 years, 8 months
  • Last seen this week
  • London, UK
20 votes

Integrating $\int \sqrt{x+\sqrt{x^2+1}}\,\mathrm{d}x$

20 votes

What equation produces this curve?

20 votes

If you know all angles and the area of the triangle, how do you find the sides?

19 votes

Function which creates the sequence 1, 2, 3, 1, 2, 3, ...

16 votes

Is there a simple function that generates the series; $1,1,2,1,1,2,1,1,2...$ or $-1,-1,1,-1,-1,1...$

14 votes

Ask about beautiful properties of $e$

14 votes

Functions that are their own inverse.

13 votes

Separable differential equations: detaching dy/dx

13 votes

Find perpendicular distance from point to line in 3D?

12 votes
Accepted

Number of ways to color the edges of a tetrahedron with two colors?

12 votes

How many numbers between 4,000 and 7,000 can be chosen using the digits [0, 8]?

11 votes

Some equations from Russian maths book.

11 votes

What is the intuition behind $\mathbb{P} (A \text{ and }B) = \mathbb{P}(A) · \mathbb{P}(B)$ if they are independent events?

11 votes
Accepted

How do you derive that the inradius in a right triangle is $r=\frac{a+b-c}2$?

10 votes

Find the summation $\frac{1}{1!}+\frac{1+2}{2!}+\frac{1+2+3}{3!}+ \cdots$

10 votes
Accepted

Solve the equation $8x^3-6x+\sqrt2=0$

10 votes

How to prove that $e^x=\sum_{k=0}^\infty \frac{x^k}{k!}$?

9 votes

How would you find the exact roots of $y=x^3+x^2-2x-1$?

9 votes

Does there exist a nontrivial rational function which satisfies $f(f(f(f(x))))=x$?

8 votes
Accepted

Am I using the right substitution to solve this differential equation?

8 votes
Accepted

What values gives the minimum area of the ellipse?

8 votes
Accepted

Calculating $\frac{1}{1\cdot 2\cdot 3}+\frac{1}{5\cdot 6\cdot 7}+\frac{1}{9\cdot 10\cdot 11}+\cdots$

8 votes
Accepted

Parametric coordinates of parabola?

8 votes

Geometric justification of the trigonometric identity $\arctan x + \arctan \frac{1-x}{1+x} = \frac \pi 4$

8 votes

Is it possible to express a vector using cross product with another vector?

8 votes
Accepted

Quickly simplify $(\sqrt{3}+1)^6+(\sqrt{3}-1)^6$

8 votes

Which principle is violated here in the logarithmic equation?

7 votes

Asking for help on a question about integral: $\int_0^\pi \frac{x\sin x}{3+\cos^2 x}\mathrm{d}x$

7 votes
Accepted

Integrate $\int\frac{1}{x}\sqrt{\frac{1-x^2}{1+x^2}}\,\mathrm{d}x$

7 votes
Accepted

Connection between curvature and arc-length

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