8 replies to this topic

[Gerard]

?'m really new in this about calculators (2 weeks) then:
have been trying to make a program and I need to isolate the result of a solve function, i get a result as {x=0.020615} to put it into a variable ant then make some operations, with this result I cant operate.
Is there any other function as eval() or similar to get only the expression? or any trick?
I've been trying to convert to a string eliminate "x=" and then use the strtoexp() but it doesn't change the type...

excuse my english, thankyou!

P.S. :What is the difference in use this and this

[Daniel (CZE)]

As you can see, result is given as list type. So you can do something like this:

solve(x=1,x)=>y

In var. y is the result {x=1}

now you can operate with expr. in var. y as with list.

You can access to result by this command: y1

If you have more expressions ({x=1,x=-1}), you can use y1, y2, ...

"(-)" and "-" is same, I think.

[Andy.Davies]

"(-)" and "-" is same, I think.

yes i belive they are:

3' /> 2' /> = 1

3' /> 2' /> = 1

aswell, with no syn errors, so i guess they are the same

[Daniel (CZE)]

I've been trying to convert to a string eliminate "x=" and then use the strtoexp() but it doesn't change the type...

You can get left or right part of expression ("=" is center) by these commands:

getLeft(EXPR)
getRight(EXPR)

so for "x=1" you'll get number 1 as: getRight(x=1)

[CrimsonCasio]

another way you could do it is like this:

solve(EQU,x)=>y
ExpToStr y,y //y is now a string
StrFind y,"=",smin
StrFind y,"}",smax
StrMid y,smin+1,y,smin-1 //the # part the y is stored in y
strToExp(y)=>y //y is a number

this is the programming method, in this case the mathmatical way is better.

[mkanter]

To get the expression (the right side of the solution you can use getRight and need not to look for the =)

solve(f(x),x)=>sol
'to make expr the same size as sol
sol=>expr
'The first expression
getRight(sol1)=>expr1
'The 2nd expression - if there is one check it with dim(sol)
getRight(sol2)=>expr2
'The 3rd expression- if there is one check it with dim(sol)
getRight(sol3)=>expr3

[Gerard]

It's great to have an answer as wide as this
Ive been trying the getright() and it's what I needed.

Thankyou.Best regards

[CrimsonCasio]

good luck

[tonyp]

solve(x=1,x)=>y

In var. y is the result {x=1}

now you can operate with expr. in var. y as with list.

You can access to result by this command: y1

By the way, this also works with ANS so you don't have to save the result to a variable, if it's to be used only once afterwards.

ANS1 will return the first list item. ANS2 the second, and so on.

tonyp AT acm.org