Fiber-optic cables are used widely for wiring in aircraft and submarines. When light passes through a fiber-optic cable, its intensity decreases with the increase in the length of the cable. If 1200 lumens of light enters the cable, the intensity of light decreases by 2.5% per meter of the cable.

Part A: Can this situation be represented by an exponential function? Justify your answer. (2 points)
Would this mean...

Question

Fiber-optic cables are used widely for wiring in aircraft and submarines. When light passes through a fiber-optic cable, its intensity decreases with the increase in the length of the cable. If 1200 lumens of light enters the cable, the intensity of light decreases by 2.5% per meter of the cable.

Part A: Can this situation be represented by an exponential function? Justify your answer. (2 points)
Would this mean...

undeadknight26 · Answer

F(x) = 1200(2.5)^x?

math&ing001 · Answer

I think it should be F(x)=1200-1200*0.025*x with x=nbr of meters of the cable

undeadknight26 · Answer

why would it be 1200-1200?

undeadknight26 · Answer

Wait no i think im doing this wrong i think im just supposed to say yes or no if it can be a exponential function.

math&ing001 · Answer

It's not 1200-1200. It decreases by 2.5% lumens per meter of the cable so it's:
F(x)=1200-1200*0.025*x=1200*(1-0.025*x)

undeadknight26 · Answer

so that means it can be represented by a exponential function right?

math&ing001 · Answer

Nope

undeadknight26 · Answer

How can i prove that?

math&ing001 · Answer

Because it decreases periodically, i wouldn't say that it could be represented by an exponential function.

undeadknight26 · Answer

a few more questions?

undeadknight26 · Answer

How could i represent this with a function?
F(x) = 1200/2.5?

undeadknight26 · Answer

i have one more after this....

math&ing001 · Answer

You can use the one I pointed above

undeadknight26 · Answer

this one?F(x)=1200-1200*0.025*x
wouldn't it have to follow y = mx + b though?

undeadknight26 · Answer

@math&ing001

math&ing001 · Answer

It does m=-1200*0.025 and b=1200

undeadknight26 · Answer

oh ok thx.

undeadknight26 · Answer

The last question is:
Some scientists are trying to make a cable for which the intensity of light would decrease by 3 lumens per unit length of the cable. Can this situation be represented by an exponential function? Justify your answer and write the appropriate function to represent this situation if 1200 lumens of light enter the cable.

math&ing001 · Answer

What do you mean by "unit length" ?

undeadknight26 · Answer

im guessing the length of the cable.

undeadknight26 · Answer

Ill make a new question...

anonymous · Answer

this messed me up ... lol

undeadknight26 · Answer

*sigh* gomen.

anonymous · Answer

@undeadknight26  did you get this question correct?