Maths in Python

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Like all programming languages, maths plays a significant part.  Today we explore maths operators and functions that use maths in our code.

Addition / Subtraction Operator

Incrementing a variable by 1 (increase by 1)

cycles = 0
cycles = cycles + 1
print(cycles)

We can shorten this code using an “augmented assignment operator”.

cycles = 0
cycles += 1
print(cycles)

Similarly, we can decrement a variable (decrease) by 1

cycles = 10
cycles -= 1
print(cycles)

Multiplication / Division Operator

Increasing by 3 times

cycles = 4
#cycles = cycles * 3
cycles *= 3
print(cycles)

Finally dividing by 2;

cycles = 16
#cycles = cycles / 2
cycles /= 2
print(cycles)

Exponents

The power of 2

cycles = 5
#cycles = cycles ** 2
cycles **= 2
print(cycles)

Modulus

Modulus gives you the remainder of any division – often used to find out if a number is even or odd.  Modulus 2 will always be zero for an even number and 1 for odd.

cycles = 11
remainder = cycles % 3
print(remainder)

Functions

Include round, absolute, power, max and min. (try each by removing the comment in front of the function)

x = 3.51
y = -4
z = 7

#result = round(x)     # <-- rounds x to nearest integer (4)
#result = abs(y)       # <-- distance of the number from zero as a whole (4)
#result = pow(8, 2)    # <-- sets result to 8^2 (64)
#result = max(x, y, z) # <-- sets result to largest var. (7)
result = min(x, y, z) # <-- sets result to smallest var. (-4)

print(result)

Classes – The Maths Class

We can import the ‘math’ module to obtain some very useful constants and functions.

For instance, if we need to use the value of π

import math
print(math.pi)     # <-- outputs the value of pi

Other mathematical operations include:

import math
x = 9.6

# -- find the square root of x
#result = math.sqrt(x)

# -- round value of x up to the ceiling, 9.6 -> 10
#result = math.ceil(x)

# <-- rounds value of x down to the floor, 9.6 -> 9
result = math.floor(x)

print(result)

Finding the circumference of a circle uses formula Circumference = 2 x π x Radius.

import math
radius = float(input("Enter the radius of the circle: "))

circumference = 2 * math.pi * radius
#print(f"The circumference of the circle is {circumference}")

# -- to round off to three decimal places
print(f"The circumference of the circle is {round(circumference, 3)}")

Exercise 1

Write code to calculate the area of a circle – ask the user for the radius of the circle.

(Area = π x r²) – ensure the result is given to 2 decimal places.

Exercise 2

Find the length of the hypotenuse of a right angled triangle after asking your user to provide the length of side a and side b. (round the answer to 2 decimal places.)

hint: c = √(a² + b²)

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