which graph represents a function whose inverse is also a function?

Question

anonymous · Answer

attachment

directrix · Answer

Use the horizontal line test to determine if a function has an inverse function. If ANY horizontal line intersects your original function in ONLY ONE location, your function has an inverse which is also a function. http://www.regentsprep.org/regents/math/algtrig/atp8/applesson.htm

anonymous · Answer

but they all look inverse

directrix · Answer

Not if you use the horizonal line test I posted above. One of the options will be the answer when you apply that test. Look again.

directrix · Answer

A big "no" for the first one because the horizontal line passes through two points of the original graph.

anonymous · Answer

i was thinking c or d? @Directrix

directrix · Answer

Me, too.

anonymous · Answer

mostly c?

directrix · Answer

But, I ruled out C because the horizontal line picked up two points of the original graph.

directrix · Answer

So,, that leaves which option as the answer?

anonymous · Answer

d?

directrix · Answer

That's what I got. look at this attached diagram.

anonymous · Answer

thanks so much

directrix · Answer

Any time I can help you, I will try.