User:Whkoh/Sandbox

Useful text
&#26032;&#21152;&#22369;

The quadratic formula
for a general quadratic equation of $$ ax^2+bx+c=0 $$ $$ x \quad = \quad \frac {-b\pm\sqrt{b^2-4ac}} {2a} $$

Area of triangle
The area of a triangle with vertices $$\left( x_1, y_1 \right)$$, $$\left( x_2 , y_2 \right)$$ and $$\left( x_3 , y_3 \right)$$ of a Cartesian coordinate system can be determined by the formula: $$ \begin{matrix} \mbox{Area of } \triangle &=& \frac {1} {2} \times \begin{vmatrix}x_1 & x_2 & x_3 & x_1 \\ y_1 & y_2 & y_3 & y_1\end{vmatrix} \\ & =& \frac {1} {2} \times \left( \left[ x_1y_2 + x_2y_3 + x_3y_1 \right] - \left[ y_1x_2 + y_2x_3 + y_3x_1 \right] \right) \end{matrix} $$

pH


\mbox{pH} = -\lg \left[ \mbox{H}^+ \right]

$$

&#x215A;

&rArr; whkoh &#91;talk&#93;  09:12, Mar 16, 2004 (UTC)

$$ \begin{matrix}20 \times 10^9 & = & 20,000,000,000 \\ \ & = & 18.626 \times 2^{30} \end{matrix} $$

Integrate
$$ \begin{matrix} \int_{0}^{\frac{\pi}{2}} \left (sin^2 x - \left (- cos^2 x\right) \right ) dx \ & = & \int_{0}^{\frac{\pi}{2}} \left (sin^2 x + cos^2 x \right ) dx \\ & = & \int_{0}^{\frac{\pi}{2}} \left (1 \right ) dx \\ & = & \left [x \right ]_0^\frac{\pi}{2} \\ & = & \frac{\pi}{2} - 0 \\ & = & \frac{\pi}{2} \end{matrix} $$

Plot
President Herney's re-election campaign is teetering on the balance. Faced by accusations of NASA budget overruns and other inefficiencies, Herney faces an uphill battle to keep his presidency. Senator Sexton, on the other hand, is buoyed after having pointed out that NASA has continually been allocated more federal funds (after overrunning their budget) and that these funds are used to fund NASA instead of public schools.

continue...

Cuisine of Singapore
The cuisine of Singapore is influenced by its four ethnic groups, the Chinese, Malay, Indian, and Eurasian. It is similar to the cuisine of Malaysia.

The four groups have a large impact on the cuisine of Singapore. Rice is widely eaten and is a staple food of many people in Singapore.