Introduction to Trigonometry

This set of flashcards encompasses essential terminologies and definitions from the lecture on triangles and trigonometry, aiming to facilitate learning and review.

Trigonometry

The branch of mathematics dealing with the relationships between the angles and sides of triangles.

Right Triangle

A triangle with one angle measuring 90 degrees.

Hypotenuse

The longest side of a right triangle, opposite the right angle.

Legs

The two shorter sides of a right triangle.

Acute Angle

An angle measuring less than 90 degrees.

Adjacent Side

The side next to the angle in question, in a triangle.

Opposite Side

The side opposite the angle in question, in a triangle.

Theta (θ)

A common variable used to represent angles in trigonometry.

Sine (sin)

The ratio of the length of the opposite side to the hypotenuse in a right triangle.

Cosine (cos)

The ratio of the length of the adjacent side to the hypotenuse in a right triangle.

Tangent (tan)

The ratio of the length of the opposite side to the adjacent side in a right triangle.

Cotangent (cot)

The reciprocal of the tangent function, equal to adjacent over opposite.

Secant (sec)

The reciprocal of the cosine function, equal to the hypotenuse over adjacent.

Cosecant (csc)

The reciprocal of the sine function, equal to the hypotenuse over opposite.

Soh Cah Toa

A mnemonic device for remembering the definitions of sine, cosine, and tangent.

Pythagorean Theorem

A formula used to find the length of a side in a right triangle: a² + b² = c².

Angle of Elevation

The angle between the horizontal line and the line of sight upwards to an object.

Angle of Depression

The angle between the horizontal line and the line of sight downwards to an object.

30-60-90 Triangle

A right triangle with angles measuring 30, 60, and 90 degrees, and sides in ratio of 1:√3:2.

45-45-90 Triangle

A right triangle with angles measuring 45 degrees each, and sides in the ratio of 1:1:√2.

trigoRatios

Relationships between the angles and sides of a triangle used to solve problems in trigonometry.