Erin is high class's user avatar
Erin is high class's user avatar
Erin is high class's user avatar
Erin is high class
  • Member for 1 year, 2 months
  • Last seen this week
  • Ottawa, ON, Canada
8 votes

Non-diagonal n-th roots of the identity matrix

7 votes
Accepted

Calculate the volume of a tetrahedron with vertices $(1,1,1)$, $(2,1,1)$, $(1,2,1)$, $(1,1,2)$

6 votes
Accepted

Finding smallest vector satisfying an equation with a dot product

6 votes
Accepted

How far does one have to zoom into an image that was rotated a certain amount of degrees in order to only see only the original pixels again?

5 votes

Determine the maximum of $f(x) = x + \sqrt{4-x^2}$ without calculus

5 votes

If $a^{2}+b^{2} \leq 4$, prove that $a+b \leq 4$

5 votes

Algorithm to determine if a 3D ellipsoid is contained within another?

4 votes
Accepted

Rotating a cone

4 votes

Minimum distance from the vertices of a quadrilateral

4 votes

Express $\sec^{-1}(x)$ in terms of $\cos^{-1}(x)$

4 votes
Accepted

If $x^2 + mx + 1 = 0$ and $x^2 + x + m = 0$ share a same root ($m \neq 1$), find $m$

4 votes
Accepted

Ratio of heights of a sphere,over and under water

4 votes

Cross section of a sphere cut by cylinder

4 votes
Accepted

Find the area of the shaded region. (Apparently this is a Chinese primary school math question!)

4 votes
Accepted

A cube is dropped on the floor, and the triangular hole created has sides of lengths $68,$ $75,$ and $77.$ Find the depth of the hole.

4 votes
Accepted

Solid enclosed by the paraboloid $\frac{y^2}{b^2}+\frac{z^2}{c^2}=2\frac{x}a$ and the plane $x=a.$

4 votes

Solving non linear equations where equations are equals

3 votes
Accepted

Prove that from $0 > a > b$ follows $0 > b^{-1}>a^{-1}$

3 votes

How to solve $3\sec(x)-2\cot(x)>0$ (trigonometric inequality)?

3 votes
Accepted

how to calculate $\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}}\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}}\sin{|x-y|}dxdy$?

3 votes
Accepted

Finding angle between vector and Oz axis if we have angles with Ox and Oy

3 votes
Accepted

If $[a]_\times$ is a matrix such that $[a]_\times b$ = $a \times b$, and $R$ is a (rotation) Matrix, how to simplify $[Ra]_\times$?

3 votes
Accepted

Finding slant length of any given point for a cone with an angled base

3 votes
Accepted

How do I find the rotation matrix between 2 normalized vectors coming from the origin

3 votes
Accepted

Fourth point of a parallelogram with corners at $\langle 1,1\rangle$, $\langle 4,2\rangle$ and $\langle 1,3\rangle$?

3 votes
Accepted

How to solve $y'''=\alpha^3 y$?

3 votes

This is a question about hyperbolas

3 votes

Finding the slope of line intersecting the parabola

3 votes
Accepted

Given a matrix, how do you find entries of M^n?

3 votes
Accepted

Show the definite integral $\int_{0}^{2\pi}\frac{\cos(t)}{\cos(t) + i \sin(t)}\;dt$ equals $\pi$

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