Sine, Cosine, and Tangent of Unit Circle

In which quadrants is the sine function positive?

• 1

• 1,2

• 2,3

• All

In which quadrants is the cosine function positive?

• 1,2

• 2,3

• 3,4

• 1,4

State a Pythagorean Identity

• a²+b²=c²

• sin²x+cos²x=1

• tan x=sin/cos

• sin x =1/cosx

The cosine of an acute angle in a triangle is the ratio of which two of its sides?

• opposite/adjacent

• adjacent/hypotenuse

• opposite/hypotenuse

• hypotenuse/adjacent

Unlike right triangle trigonometry, sine and cosine may be negative. Thinking about how sine, cosine, and tangent relate to (x,y) coordinate pairs on the unit circle, find the quadrants where: sine is positive: ​ (a)   ​& (b)   sine is negative: ​ ​ (c)   &​ (d)  

• I

• II

• III

• IV

Unlike right triangle trigonometry, sine and cosine may be negative. Thinking about how sine, cosine, and tangent relate to (x,y) coordinate pairs on the unit circle, find the quadrants where: cosine is positive: ​ (a)   ​& (b)   cosine is negative: ​ ​ (c)   &​ (d)  

• I

• IV

• II

• III

Unlike right triangle trigonometry, sine and cosine may be negative. Thinking about how sine, cosine, and tangent relate to (x,y) coordinate pairs on the unit circle, find the quadrants where: tangent is positive: ​ (a)   ​& (b)   tangent is negative: ​ ​ (c)   &​ (d)   ​

• I

• III

• II

• IV

What is the angle measure, in degrees, at the red marking on the unit circle?

• 30°

• 45°

• 60°

• 90°

Based on the unit circle, what is the value of cos?

• y

• x

• x/y

• y/x

Based on the unit circle, what is the value of tan?

• y/r

• x/r

• r/y

• y/x