TI Program

This is driving me mad...

Can anyone tell me how to do the following equation on a calculator?

1 / [1 + e-(1*0.5+1*0.4-1*0.8)]

Cheers,
TK

Quote:

---

Originally Posted by tomjkear

This is driving me mad...

Can anyone tell me how to do the following equation on a calculator?

1 / [1 + e-(1*0.5+1*0.4-1*0.8)

Cheers,
TK

---

Hello,

There is no equation in there... oO
And which calculator ?

Quote:

---

Originally Posted by Moo

Hello,

There is no equation in there... oO
And which calculator ?

---

That is a sigmoidal function.

I do not understand the purpose / value of e?

Quote:

---

Originally Posted by tomjkear

That is a sigmoidal function.

I do not understand the purpose / value of e?

---

Oh, I see

e has a value approaching 2.7. Actually it's e^(...).
It's the exponential function : Exponential function - Wikipedia, the free encyclopedia

So if you want to enter the function in your calculator, it should be :

1/(1+e^(-(1*0.5+1*0.4-1*0.8)))

Quote:

---

Originally Posted by Moo

Oh, I see

e has a value approaching 2.7. Actually it's e^(...).
It's the exponential function : Exponential function - Wikipedia, the free encyclopedia

So if you want to enter the function in your calculator, it should be :

1/(1+e^(-(1*0.5+1*0.4-1*0.8)))

---

Thanks.

I know the result should be 0.5250 according to the textbook I am using. But doing the above in my calculator returns 0.5 for some reason.

Another similar example that is given is:

1/(1+e^(-(1*0.9+1*1.0+1*0.1)))

This should return 0.8808 but also returns 0.5 on my calculator.

If it helps the calculator is a Sharp EL-530L.

Quote:

---

Originally Posted by tomjkear

Thanks.

I know the result should be 0.5250 according to the textbook I am using. But doing the above in my calculator returns 0.5 for some reason.

Another similar example that is given is:

1/(1+e^(-(1*0.9+1*1.0+1*0.1)))

This should return 0.8808 but also returns 0.5 on my calculator.

If it helps the calculator is a Sharp EL-530L.

---

I don't know this calculator, so I don't know what e represents for them...

Try typing :

1/(1+2.71828183^(-(1*0.9+1*1.0+1*0.1)))

(because e ~ 2,71828183)

Quote:

---

Originally Posted by Moo

I don't know this calculator, so I don't know what e represents for them...

Try typing :

1/(1+2.71828183^(-(1*0.9+1*1.0+1*0.1)))

(because e ~ 2,71828183)

---

Thanks for the help.
I have tried a diffferent calculator and it returns the correct results.
Not sure what is the matter with mine but I will get a replacement for the exam :)