Precalculus Trigonometric Equations

Choose a good way to start solving this equation

tanx sin²x = 2 tanx

• divide tanx from both sides

• factor out tanx

• subtract 2 tanx from the left and then factor tanx out

• cancel sin²x out

Factor 0 = sin²x − sinx

• 0 = sinx(sinx)

• 0 = sinx(1 − sinx)

• 0 = cosx(sinx − 1)

• 0 = sinx(sinx − 1)

csc²x = 2 is equivalent to sin²x = ½

• True

• False

Solve on the Interval [0,2π)
     tan(x) + 1 = 0     

• x = π/4, x = 5π/4

• x = π/4, x = 3π/4

• x = π/2

• x = 3π/4, x = 7π/4

Which equation shows how you would use the law of sines to find side c?

Two stakes are holding a small blimp in place. Stake A measures an angle of elevation of 49o and Stake B measures an angle of elevation of 58o. If the string attached to Stake A has a length of 148 feet, what is the length of the string attached to Stake B? (a)  

• 152.7 feet

• 166.3 feet

• 157.3 feet

• 131.7 feet

To approximate the length of a marsh, a surveyor walks 425 meters from point A to point B. Then the surveyor turns 65º and walks 300 meters to point C. Approximate the length AC of the marsh.

• 250 m

• 615 m

• 500 m

• 790 m

Choose the correct ratio.

• sin^-1(9/20)

• tan^-1(9/20)

• cos^-1(9/20)

• cos^-1(20/9)

• π/5

• π

• 5

• 5π

• 2π/5

Which law would you use? (a)  

• Law of Sines

• Law of Cosines