MathType is a Home & Education software developed by Design Science. After our trial and test, the software is proved to be official, secure and free. Here is the official description for MathType:

EditByMarydown: MathType is a powerful interactive tool for Windows and Macintosh that lets you create mathematical notation for word processing, web pages, desktop publishing, presentations, and for TeX, LaTeX, and MathML documents.

Features & Benefits
Here are just a few of MathType's many features:

Works with Many Applications
While many MathType users create equations for Microsoft Word documents and PowerPoint presentations, MathType also works with many, many other applications and websites and we are adding more and more every day:

Add equations to Quark and InDesign documents.
Copy equations from websites like Wikipedia, PlanetMath, etc. for use in your own work. You can author new equations for those websites as well.
Copy equations from Mathematica or Maple into your research.
Use equations to label DeltaGraph scientific graphs and Excel spreadsheets.
Work with TeX and LaTeX editors and documents.

More Symbols, Templates, and Fonts
More Fonts: MathType has hundreds more symbols and templates than Equation Editor. Beside our exclusive Euclid™ math fonts, you can also make use of the 1000s of math symbols in fonts already on your computer, as well as math fonts you can download from the Internet.
Find Symbols: MathType's Insert Symbol dialog allows you to explore the available symbols and insert them with a click or keystroke.

Three Ways to Create Equations
Point-and-Click Editing with Automatic Formatting: Equations can be created quickly by choosing templates from MathType's palettes and typing into their empty slots. MathType applies mathematical spacing rules automatically as you type.
Type TeX or LaTeX into MathType: You can also type TeX into MathType's editing window. TeX editing can be mixed with point-and-click editing so you get the best of both worlds. You can also paste in equations from existing TeX documents.