My boyfriend gave me a gift.

Everyone was surprised by the news.

He is an expert in analytical mechanics and deeply understands its theory.

Numerical analysis is a branch of mathematics that studies techniques and theories for solving mathematical problems numerically.

He is majoring in analysis at university.

Complex analysis is a branch of mathematics that studies functions of complex numbers.

Real analysis is a branch of mathematics that studies the properties of real numbers and the functions on them.

The theory of harmonic oscillators is a fundamental concept in physics.

He likes to take a walk in the park at dusk.

Functional analysis is a branch of mathematics that studies the properties of functions in infinite-dimensional spaces.