Why python can't show the exact value of sin function?

Question

from math import sin, pi
print(sin(2*pi))

This code includes the value of sin(2pi) which equals to 0, but why python show this -2.4492935982947064e-16? and how to fix it? Is it just the problem of my computer?

FYI: `2*pi` ≠ 2π. See, for example, ["What Every Computer Scientist Should Know About Floating-Point Arithmetic"](https://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html) — Warren Weckesser, Apr 18 '20 at 11:48
Thank you. Maybe there are no solution to calculate the exact value(0) of sin(2pi) because of the floating-point problem. — KKR, Apr 18 '20 at 12:19

score 1 · Answer 1 · answered Apr 18 '20 at 11:52

1

pi is not equal with π. you can use sympy instead.

from sympy import sin, pi
print(sin(pi))  # 0

answered Apr 18 '20 at 11:52

SMortezaSA

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Why python can't show the exact value of sin function?

1 Answers1