Chapter 9 Trigonometric Ratios

Question 1

what is the version of the cosine rule to find a missing side?

Answer 1

a^2 = b^2 + c^2 - 2bccosA

Question 2

what is the version of the cosine rule to find an angle?

Answer 2

cosA = b^2 + c^2 - a^2 / 2bc

Question 3

what is the version of the sine rule to find a missing side?

Answer 3

a/sinA = b/sinB = c/sinC

Question 4

what is the version of the sine rule to find an angle?

Answer 4

sinA/a = sinB/b = sinC/c

Question 5

what is the formula for area of a triangle?

Answer 5

1/2absinC

Question 6

what type of graphs are the graphs of sine, cosine and tangent?

Answer 6

period graphs, so they repeat themselves after a certain interval

Question 7

what are the qualities of the graph of y = sinθ

Answer 7

• repeats every 360 degrees and crosses the x axis at: …, -180, 0, 180, 360, …
• has a minimum value of -1 and a maximum value of 1

Question 8

what are the qualities of the graph of y = cosθ

Answer 8

• repeats every 360 degrees and crosses the x axis at: …, -90, 90, 270, 450, …
• has a minimum value of -1 and a maximum value of 1

Question 9

what are the qualities of the graph of y = tanθ

Answer 9

• repeats every 180 degrees and crosses the x axis at: …, -180, 0, 180, 360, …
• has no maximum or minimum value
• has vertical asymptotes at x = -90, x = 90, x = 270 ect