In linear algebra, triangular matrices play a very important role.

There is a complex love triangle between them.

He is good at solving trigonometry problems.

Trigonometric functions are one of the basic concepts in mathematics.

He is good at solving problems of trigonometric functions.

He trains his deltoid muscles at the gym every day.

Everyone, please have a good new year.

Finding the Summer Triangle is helpful for remembering constellations.

The Winter Triangle is shining in the night sky.

In linear algebra, the upper triangular matrix plays a very important role.