CODEWITHSUNDEEP
pythonmathpython-2.7
user1850156
user1850156

Reputation:

Compute Parabola using python

def parabola(h, k, xCoordinates):

h is the x coordinate where the parabola touches the x axis and k is the y coordinate where the parabola intersects the y axis and xCoordinates is a list of x coordinates along the major axis. The function returns a list of y coordinates using the equation shown below. There will be one y coordinate for each x coordinate in the list of x coordinates.

y(x, h, k) = a(x − h)2, where a =k/h2

I know how to work in python as i already compute the area ,

def computeArea(y_vals, h):
    i=1
    total=y_vals[0]+y_vals[-1]
    for y in y_vals[1:-1]:
        if i%2 == 0:
            total+=2*y
        else:
            total+=4*y
        i+=1
    return total*(h/3.0)
y_values=[13, 45.3, 12, 1, 476, 0]
interval=1.2
area=computeArea(y_values, interval)
print "The area is", area

But the question above is hurting me because its pure mathmatics , i just want little bit help

Upvotes: 3

Views: 4702

Answers (2)

Michael Flyger
Michael Flyger

Reputation: 331

The answer given by Martijn Pieters is good.

If you're struggling a little with the concept I find this example to be very easy to understand (using the vertex form equation):

x = range(-10,10)
y = []

a = 2 # this is the positive or negative curvature
h = 0 # horizontal offset: make this term +/- to shift the curve "side to side"
k = 0 # vertical offset: make this term +/- to shift the curve "up to down"

for xi in x:
    y.append(a * (xi + h)** 2 + k)

You can plot it with pylab.

Upvotes: 2

Martijn Pieters
Martijn Pieters

Reputation: 1121446

You can use the ** power operator to square values:

y = (k / h ** 2) * (x - h) ** 2

where ** exponentiation has a higher precedence than multiplication or division.

So for a series of x coordinates, that'd be:

def parabola(h, k, xCoordinates):
    return [(k / h ** 2) * (x - h) ** 2 for x in xCoordinates]

Upvotes: 2

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