Applying the Unit Circle - Radian Measure

Question

P = (x,y) is the point on the unit circle that corresponds to a real number t. Find the exact values of the six trigonometric functions of t.

1) (-2/5, √21/5)

2) (-√2/2, √2/2)

Answer 1

If you are given co-ordinates (x,y), what is the tangent (tan) of the angle which the line through (x,y) makes with the x-axis?

You will also need the mnemonic AllSinTanCos which reminds you which trig functions are positive in which quadrant.

Answer 2

In the unit circle

sine is equal to y

cosine is equal to x

tangent is equal to y / x

cotangent is equal of x / y

secant is equal to 1 / x

cosecant is equal to 1 / y