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How to store an equaion in a variable?

Unread postPosted: 24 Jul 2020, 14:00
by arabajamelabañera
Dear all,
I am new to the TI-Nspire CX CAS. Could you advice me on how to store an equation in a variable? Mathematica uses ":=" and "==", e.g.
Code: Select all
myeq := 1/a == b * log(a + 4)

in order to use it later on in an expression like
Code: Select all
solve(myeq,a) | b = 10

Thank you for advice.

Re: How to store an equaion in a variable?

Unread postPosted: 24 Jul 2020, 15:01
by Hisham
Image

Best,
Hisham :)

Re: How to store an equaion in a variable?

Unread postPosted: 24 Jul 2020, 15:16
by arabajamelabañera
Hi Hisham,
I don't get it... where has "eq"been assigned, and what is "subst"?
Could you give me a more concrete example or explain how it is supposed to work?

Re: How to store an equaion in a variable?

Unread postPosted: 24 Jul 2020, 16:23
by Bisam
First, the affectation symbol is :=, would it be for a function or a variable.
Then, the test for equality is done with =, not == which will run to a syntax error.

E.g. :
Code: Select all
myeq := 1/a = b * log(a + 4)
solve(myeq,a) | b = 10

Re: How to store an equaion in a variable?

Unread postPosted: 24 Jul 2020, 17:24
by arabajamelabañera
Hi Bisam, thank you for your reply.
Yes, I agree. But when I type it the way you propose, I get an error:
"Argument must be an expression."
Which implies that equations can not be stored and recalled in a convenient way?!?

Re: How to store an equaion in a variable?

Unread postPosted: 24 Jul 2020, 18:30
by nspiredev500
Maybe you mistyped something, it works for me.

Re: How to store an equaion in a variable?

Unread postPosted: 27 Jul 2020, 17:01
by arabajamelabañera
Thank you all for your time.
Miraculously, it is working now...
a := b + c = d
gives
b + c = d
I really do not know, why I had to write this post.