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# Your Engineering Calculations Deserve Better Are you still relying on spreadsheets for engineering calculations? Then it’s time for an upgrade. Discover PTC Mathcad, where maths meets engineering with clarity and precision.

Engineers often use spreadsheets for calculations, but not without some headaches. Here’s a spreadsheet that one engineer created to drive part geometry for a wing in a Creo Parametric model:

It doesn’t look too bad, right? Looks, as we know, can be deceiving. Those nice-looking equations for the lift and lift coefficient are actually images which are pasted onto the sheet. If you look in the formula bar, the lift calculated in cell G3 is actually achieved by:

=E80.5E11E10^2E1

That’s not easy to read. That’s also not really how engineers work. We want to use variables, subscripts, exponents, Greek letters, and so on – real mathematical notation, just like the way you would write on a whiteboard or a sheet of graph paper.

Look at lines 9 and 10. The wing speed is given in miles per hour and then in feet per second. The spreadsheet here is now actually converting units. We don’t see that work being performed, and having two different velocities in our calculation methodology can be confusing.

Furthermore, writing formulas using cells instead of variables and writing them in a spreadsheet’s cluttered, non-intuitive notation is potentially a huge potential source of error. Similarly, the unit conversion for the velocity can introduce errors as well. For example, a mismatch of units for the trajectory calculations resulted in the Mars Climate Orbiter, a \$327 million project, burning up upon entry into the Martian atmosphere.

From an aesthetic standpoint, do you want to share your calculations with others in a format more associated with accounting and taxes rather than engineering and manufacturing? Let’s be frank: Spreadsheets don’t leave an impactful impression.

### The Alternative

Smart engineers don’t rely on spreadsheets alone. Here is the same work in a PTC Mathcad worksheet:

The calculations are presented in an interface resembling the same computational pads engineers use daily. The variables are defined using letters (both English and Greek, uppercase and lowercase) and subscripts. The worksheet shows the functions for the coefficient of lift and lift force and evaluates them inline. The work is also documented with text and images, capturing our intent.

We can define variables in whatever units we want, run calculations, and view the results in any other units. We don’t have to work within a single designated unit system since PTC Mathcad understands and reconciles different unit systems. This worksheet was set up using the metric system, but the lift force was evaluated using pounds force instead of newtons. Combining and matching units and knowing they will be handled automatically gives an engineer incredible power and freedom.
In this single, easily readable document, we have:

• Reference images that explain the problem we’re solving.
• Our maths is presented in a logical, step-by-step flow.
• Supplemental text that explains our engineering assumptions, decisions, and methodologies.

• Over 400 built-in functions covering a wide range of categories, including Statistics, Data Analysis, Signal Processing, Design of Experiments (DOE), and Differential Equations
• The ability to perform calculus, including derivatives integrals, summations, and limits.
• Easy programming capability that includes conditional logic and looping constructs to define your own complex functions that return single values, vectors, or matrices.
• PTC Mathcad also has libraries that include examples of how to set up and solve various engineering and advanced mathematical problems.

Once you create your own worksheets, you can reuse them and share them with others. In this way, you’re building your own library of resources for future work.

Calculations are at the heart of engineering. PTC Mathcad is mathematical software that lets you easily perform, analyse, document, and share your calculations. Select Select Danish English (UK) Finnish German Norwegian Swedish