### Author Topic: Properties of logarithms on the TI nspire  (Read 1506 times)

0 Members and 1 Guest are viewing this topic.

#### Kyle Kelly

• LV1 Newcomer (Next: 20)
• Posts: 12
• Rating: +0/-0
##### Properties of logarithms on the TI nspire
« on: April 10, 2019, 06:10:36 am »
Is it possible to make the TI-nspire apply properties of logarithms in order to rewrite multiple logs as one (the sum) or rewriting one log as multiple logs (the difference)?

I would assume the CAS version would be able to do this but I can't for the life of me figure out how. Is the feature built in the calculator or would you have to program it?
« Last Edit: April 10, 2019, 06:15:41 am by Kyle Kelly »

#### Xeda112358

• they/them
• Moderator
• LV12 Extreme Poster (Next: 5000)
• Posts: 4642
• Rating: +717/-6
• Calc-u-lator, do doo doo do do do.
##### Re: Properties of logarithms on the TI nspire
« Reply #1 on: April 10, 2019, 10:33:22 am »
I think the nspire can collapse multiple logs into one (normal behavior), but extracting you'd have to program it yourself. If it is just integer inputs, you can use one of the nspire's factor() commands to factor the number and then manually construct a sum of logs.

#### Kyle Kelly

• LV1 Newcomer (Next: 20)
• Posts: 12
• Rating: +0/-0
##### Re: Properties of logarithms on the TI nspire
« Reply #2 on: April 10, 2019, 10:48:35 am »
I think the nspire can collapse multiple logs into one (normal behavior), but extracting you'd have to program it yourself. If it is just integer inputs, you can use one of the nspire's factor() commands to factor the number and then manually construct a sum of logs.

Okay to combine multiple logs into one how would i do it?

For example: 5 log base 3(y) - log base 3(x-4)

https://imgur.com/a/Cxvkuax picture for reference and the solution i'm trying to get

#### Xeda112358

• they/them
• Moderator
• LV12 Extreme Poster (Next: 5000)
• Posts: 4642
• Rating: +717/-6
• Calc-u-lator, do doo doo do do do.
##### Re: Properties of logarithms on the TI nspire
« Reply #3 on: April 10, 2019, 11:33:28 am »
Oh, I just tested it out on my calc and it didn't simplify :|

What did work is when I did:
Code: [Select]
log(3^(5*log(y,3)-log(x-4,3)),3)