Trigonometry is a branch of mathematics that deals with triangles, particularly those plane triangles in which one angle has 90 degrees (right triangles). Trigonometry deals with relationships between the sides and the angles of triangles and with the trigonometric functions, which describe those relationships.

Trigonometry has applications in both pure mathematics and in applied mathematics, where it is essential in many branches of science and technology. It is usually taught in secondary schools either as a separate course or as part of a precalculus course. Trigonometry is informally called "trig".

A branch of trigonometry, called spherical trigonometry, studies triangles on spheres, and is important in astronomy and navigation
Let's see one of the trigonometry examples
Question:-

solve for x

2 sin²x- sinx-1=0

Answer:-

We may use some trigonometry formulas to solve this.
Put sinx = z in the given equation ,you get

2z²-z-1 =0

2z²-2z+z-1=0

2z(z-1)+1(z-1)=0

(z-1)(2z+1)=0

either z-1=0 or 2z+1=0

so z=1 or z= -1/2

since z = sinx we get

sinx = 1 = sin π/2 or sinx = -1/2 = sin(π+π/6)

x= π/2 or x= π+π/6

so x= 90° or 210°