The function ƒ(x)=a^x+4 will never cross the x-axis.
A. True
B. False

Question

The function ƒ(x)=a^x+4 will never cross the x-axis.
  		A. 	True
  		B. 	False

anonymous · Answer

True

mathteacher1729 · Answer

Have you tried graphing this for various values of a? 

Geogebra can do this quickly and easily. (and freely).

anonymous · Answer

thank you, and yes i did i just didnt know if that was how to actually do it or not

anonymous · Answer

http://www.wolframalpha.com/input/?i=plot+y%3D5%2C+y%3D2^x%2B4%2Cy%3D3^x%2B4%2Cy%3D4^x%2B4

mathteacher1729 · Answer

If you try solving 0 = a^x + 4 for x 

You will have log base a of -4 = x 

But you can't have a negative base to a logarithm. (that's how it's defined. :)

anonymous · Answer

You can have negatives in a log :P (digresses)

mathteacher1729 · Answer

True true.  But we want the log function to be single-valued and return a real result. :)

anonymous · Answer

Yeap :P