Q) Find domain of 2^x + 2^y = 2 .

A) 2^x + 2^y = 2

2^x = 2 - 2^y

x log2 = log (2 - 2^y)

x = log(2 - 2^y) / log 2

x = log (2 - 2^y) to base 2

2 - 2^y is always <= 2...... as 2^y least value will tend to 0.

log (2 - 2^y) to base 2 will lie in (-infinity, 1)

So domain is (- infinity, 1)

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