Ruthenia Empire. November 17, 1927. 1400 HRS.

Pleasant rays of sunlight stream into Alexander's office who are scribbling mathematical equations on the board. Tiffania is writing on her notes while at the same time listening attentively to Alexander's words.

"Well first and foremost, you must grasp one of the basics and at the same time important to understand for future engineering topics. Differentiation and integration. So what's the difference between the two? Well for starters, integration is used to find an area underneath a curve while differentiation is used to find the gradient of the curve," Alexander fluidly explained as Tiffania nodded her head in understanding.

Alexander continued. "So imagine this, a rectangle is drawn by a line in a cartesian plane. You are tasked to find the area, what would you do?" he asked.