# Inquiry about Symbolics.jl

**URL:** <https://discourse.julialang.org/t/inquiry-about-symbolics-jl/114331>\
**Category:** General Usage\
**Tags:** question\
**Created:** [May 16, 2024, 12:13am UTC](https://discourse.julialang.org/t/inquiry-about-symbolics-jl/114331 "2024-05-16T00:13:52Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![cnf](https://avatars.discourse-cdn.com/v4/letter/c/b38774/32.png) [@cnf](https://discourse.julialang.org/u/cnf)\
**Post date:** [May 16, 2024, 12:13am UTC](https://discourse.julialang.org/t/inquiry-about-symbolics-jl/114331/1 "2024-05-16T00:13:52Z")

</div>

I am running Julia 1.6.7 on a Linux machine and  
trying to use the Symbolics.jl package.

Any assistance with the following would be appreciated.

(1) The function simplify() does not simplify the  
following trigonometric expression to -1. How can this  
simplification be achieved?

julia\> y = -(sin(x1t))^2 - (cos(x1t))^2  
-(cos(x1(t))^2) - (sin(x1(t))^2)

julia\> Symbolics.simplify(y)  
-(cos(x1(t))^2) - (sin(x1(t))^2)

(2) The function expand() does not seem to expand  
trigonometric functions. Is there a way to achieve  
such expansions?

julia\> Symbolics.expand(sin(x1t+x2t))  
sin(x1(t) + x2(t))

julia\> Symbolics.expand(cos(x1t+x2t))  
cos(x1(t) + x2(t))

(3) How can irrational values, eg. sqrt(2), exp(1),  
etc, be represented and manipulated exactly in  
Symbolics.jl?