1) KEN: Y doesn’t go below 0 because when you square a number, it’s always positive or at least 0 as a result. Something times itself is always 0 or positive, never negative.
object: f(x) = x^2
domain: (-inf, +inf)
range: (0, +inf)
2) KEN: a square root has to be positive for both x and y
object: f(x)=x^1/2
domain: (0, +inf)
range: (0, +inf)
3) KEN: log is growth and growth can’t start at a negative, so its domain will at minimum be 0 and will always be positive because growth doesn’t start before it starts.
object: f(x) = log(x)
domain: (0, +inf)
range: (-inf, +inf)
4) KEN: the exponent can be positive or negative so the domain can be anything positive or negative. However, its range can’t be lower than 0 because there’s no powers that give you a result lower than 0.
object: f(x)=a^x
domain:(-inf, +inf)
range:(0, +inf)
5) KEN: all numbers _other than_ 0.
object: f(x)=1/x
domain: (-inf, 0)
range: U (0, +inf)