Domain & Range Help?

Question

1. Find Domain And Range Of
y = 4*(2^x)......4 times 2 to the x power

2. Find Domain And Range Of
y = 2 / (x-1), for -5<=x<=4

2b. what will the value of y never be?

Answer 1

1)4*( 2^x) since y is defined for every x so domain is R
since 2^x cant be negative so range is R+

2)y=2/x-1 x=[-5,4]
f(x) not defined for x=1 domain=[-5,4]-(1)
since f(x) at x-->1 f(x)=-infinity and at x=4 f(x)=2/3
so range is (-infinity,2/3]

Answer 2

1)domain R and range R + (R+ means set of all POSITIVE real numbers) = ] 0 , ∞ [

2a) domain [ - 5 , 4] ~ {1} and range ]-∞, -1/3] U [2/3, ∞ [
or range R ~] -1/3 , 2/3[
2b) ] -1/3 , 2/3[

Answer 3

´1) D)all real numbers,Rall positive real numbers
2)D all the interval except x=1 range from -infinity to + infinity except 0<=y<3/2 and and -1/3