Characteristic Function Symmetric Sign

Problem

For a random variable taking values +1 and -1 with equal probability, the characteristic function is E[e^{i t X}] = cos(t).

Given t, return the value.

Hint

Average the complex exponentials of opposite signs.

case 1

in: [0]

expected: 1

case 2

in: [0.5]

expected: 0.8775825618903728

case 3

in: [1]

expected: 0.5403023058681398

Starter codePython

def characteristic_function_symmetric_sign(t):
    # Your code here
    pass

3 test cases · run your code against them in the editor