physics/continuum_mechanics: Added sympy functions for cos and sin instead of using the math module

[AdvaitPote]

References to other Issues or PRs

Fixes #24038

Brief description of what is fixed or changed

Replaced math.sin and math.cos by their respective SymPy functions. This way Symbolic functions are used for calculations in the solve method.

Other comments

Release Notes

• physics.continuum_mechanics
  • Added Symbolic Functions in the solve method for calculations instead of the math module

[sympy-bot]

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• physics.continuum_mechanics
  • Added Symbolic Functions in the solve method for calculations instead of the math module (#24039 by @AdvaitPote)

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#### References to other Issues or PRs
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Fixes #24038

#### Brief description of what is fixed or changed
Replaced `math.sin` and `math.cos` by their respective SymPy functions. This way Symbolic functions are used for calculations in the `solve` method. 

#### Other comments


#### Release Notes

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  * Added a new solver for logarithmic equations.

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<!-- BEGIN RELEASE NOTES -->
* physics.continuum_mechanics
  * Added Symbolic Functions in the `solve` method for calculations instead of the `math` module
<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.

[github-actions]

Benchmark results from GitHub Actions

Lower numbers are good, higher numbers are bad. A ratio less than 1
means a speed up and greater than 1 means a slowdown. Green lines
beginning with + are slowdowns (the PR is slower then master or
master is slower than the previous release). Red lines beginning
with - are speedups.

Significantly changed benchmark results (PR vs master)

Significantly changed benchmark results (master vs previous release)

       before           after         ratio
     [41d90958]       [69532d2e]
     <sympy-1.11.1^0>                 
-         992±4μs          626±1μs     0.63  solve.TimeSparseSystem.time_linear_eq_to_matrix(10)
-     2.84±0.01ms         1.16±0ms     0.41  solve.TimeSparseSystem.time_linear_eq_to_matrix(20)
-     5.68±0.01ms         1.71±0ms     0.30  solve.TimeSparseSystem.time_linear_eq_to_matrix(30)

Full benchmark results can be found as artifacts in GitHub Actions
(click on checks at the top of the PR).

[moorepants]

LGTM. I recommend adding examples and tests with only symbolics in a future pull request also.