3k views

### Express in terms of a new variable [closed]

I have a simple expression: s=4a(x+y)^3 I want to express s in terms of b where b=x+y. That is s will become 4ab^3. How to achieve this in Mathematica?
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### Solving for a constant multiplier of a variable [duplicate]

I would like to make this manipulation: Solve[r Sin[α[t]] + l Cos[ϕ[t]] Sin[γ[t]] == 0, l*Cos[ϕ[t]]] But it seems that the ...
59 views

### Is there a way to use identities in Mathematica efficiently? [duplicate]

Imagine I have defined a variable l=p/(a*b) Let's say I perform some operations, and I get the final answer to be p/a. But all I ...
88 views

### Substitution inside an expression [duplicate]

I'm trying to get mathematica to replace an expression with a reduced form. I wanted to replace $(k/w)$ with $h$ in a particular expression, and I've tried something like: ...
48 views

### Reducing Output length by introducing new variables [duplicate]

I have outputs like "expression/(1+3*c^2) +anotherexpression/(1+3*c^2)" and so on. Is there any way to set 1/(1+3*c^2)=A where A is a new variable so that the output reads like "A*expression+A*...
3k views

### How to write a variable in terms of the other [duplicate]

I have an equation that defines a variable like y=4x+a. I had another equation, z=x+2+4, I would like to know if there is a way in Mathematica to get an expression in which z= a*y+C, in which a and C ...
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### How does PacletInstall work? And is it possible to find packages using PacletInstall?

It seems that many packages published could be installed using PacletInstall . For example, from this Rubi install instruction webpage, we could see the comman: ...
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### Do replacement only on certain specific forms

If I want to replace, say, a with a1 + a2 in an expression, I can write ...
36 views

### replacement rules don't account for signs [duplicate]

I would like to make a single replacement rule that disregards the sign. I have the following expression: ...
141 views

### How to Pattern Match complicated patterns? [closed]

How can I get the output expressed in terms of p1 and p2 instead of exponentials? ...
229 views

### How to simplify expressions

I read several similar posts but I have not found a solution yet. However, I think that my problem should be quite easy. So here we are. Relations ...
90 views

### Introducing new variables implicitly [duplicate]

I have a calculation expr111 = cs[giso, xiso, 1, 1, 1] that gives the result -((k x)/(2 (1 + 1/4 k (x^2 + y^2 + z^2)))) I ...
62 views

### Assign a variable to an expression in Mathematica

I have the following matrix {{a^2 + b + \[Sqrt](m + n) + 5, 23 x + 7 a}, {14 b, a^2 + b + \[Sqrt](m - n) + 5}} I want to replace the expressions ...
Say I have an expression $a+b+a\times b$ and I define $c:= a\times b$. How do I get Mathematica to write $a+b+a\times b$ in terms of $c$, i.e. $a+b+c$?