Introduction to...

Given $$\cos\theta = \dfrac{2}{3}$$, find $$\sec\theta$$.

The value of $$A$$ is______, if $$\tan A$$ is undefined

The value of $$\cos 90^{\circ}$$ is ______.

The value of $$\text{cosec } 90^{\circ} =$$

The history of trigonometry goes back to the earliest recorded mathematics in Egypt and _____.

Trigonometry is used mainly due to the purpose of time keeping and _____.

The term trigonometry was first invented by the German mathematician ______.

Trigonometry is a branch of mathematics that studies relationships involving lengths and ______ of triangles.

The first recorded use of trigonometry came from the Hellenistic mathematician ________________.

What is the value of $$\cos\theta \times\sec\theta$$ ?