To display an element create an r-display, which will just render the named variable as text.
<r-display name="x"></r-display>
This is a number that is dynamic: .
Try setting the value of $x$ with the range input:
You can also transform the value of a variable before you format it.
For example, you might want to say that the admission to a park is 'free' when the value == 0.
The park admission is
.
You can also use this transform to say that the park admission is
.
This is also quite useful if you want to use the transform to index into an array , in this case emoji array - but it could be numeric too!
There is code
>>> import numpy as np
>>> a = np.arange(15).reshape(3, 5)
>>> a
array([[ 0, 1, 2, 3, 4],
[ 5, 6, 7, 8, 9],
[10, 11, 12, 13, 14]])
I would have written a shorter letter, but I did not have the time.
And Equations
The product of
and
is
When you eat
cookies,
you consume
calories.
Drag me to expand the Taylor Series:
x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}
And Demos
$m$ =
$b$ =
y &= m \times x + b \\
y &=
-x+10
Coordinate Transformation
A good example of this is changing from a radial coordinate system to Cartesian.
Cartesian Coordinate System
$x$
$y$
Radial Coordinate System
$r$
$\theta$
°
Cartesian Update- $x$
x =
<r-dynamic :value="x" :change="{x: value}"></r-dynamic>
Cartesian Update - $y$
y =
<r-dynamic :value="y" :change="{y: value}"></r-dynamic>
Radius Update
r &= \sqrt{x^2 + y^2} = \\
x &= r \cos(\operatorname{atan2}(y, x)) = \\
y &= r \sin(\operatorname{atan2}(y, x)) =
<r-dynamic :value="Math.sqrt(x*x + y*y)" :change="{
x: value * Math.cos(Math.atan2(y, x)),
y: value * Math.sin(Math.atan2(y, x))
}"></r-dynamic>
Theta Update
\theta &= \operatorname{atan2}(y, x) = \\
x &= \sqrt{x^2 + y^2} \cos( \theta ) = \\
y &= \sqrt{x^2 + y^2} \sin( \theta ) =
<r-dynamic :value="Math.atan2(y, x)" :change="{
x: Math.sqrt(x*x + y*y) * Math.cos(value),
y: Math.sqrt(x*x + y*y) * Math.sin(value)
}"></r-dynamic>
Sin and Cos
In trigonometry, a
unit circle
is the circle of
radius
one centered at the origin
$(0, 0)$ in the Cartesian coordinate system. Let a
line
through the
origin,
making an
angle,
of $\theta$=
with the positive half of the x-axis, intersect the
unit circle.
The
x-coordinates
and
y-coordinates
of this point of intersection are equal to
$\cos(\theta)$
and
$\sin(\theta)$,
respectively.
See Wikipedia.