The domain of definition of the function y(x) given by the equation $2^x + 2^y = 2$ is :
Answer & explanation
Correct answer: option 4
The correct answer is option 4: $-\infty<x<1$
$2^x + 2^y = 2$
$⇒ y = \log_2(2 -2^x)$
So, $2 – 2^x>0 ⇒ x < 1$
$⇒x∈(-∞,1)$
Hence (4) is the correct answer.