trigonometry
posted by yoshi .
3. write tan (π/4β) as a function of β only.
8. write cos(λ+ π/3) as a function of λ only.
16. Write cos(–83°) as a function of a positive angle.
23. Write sin(125°) in terms of its cofunction. Make sure your answer is a function of a positive angle.
31. Find the exact value of sin(195°).

3.
tan (π/4β) = (tanπ/4  tanβ)/(1+tanπ/4 * tanβ) = (1tanβ)/(1+tanβ)
8.
cos(λ+ π/3) = cosλ cosπ/3  sinλ sinπ/3
= 1/2 cosλ  √3/2 sinλ
16.
Since cos(x) = cos(x),
cos(83°) = cos(83°)
23.
sin(x) = cos(90°x), so
sin(125°) = cos(90°125°) = cos(35°) = cos(35°)
31.
sin(195°) = sin(180°+15°) = sin(15°) = sin(30°/2)
= √((1cos(30°))/2)
= √(1√3/2)/2)
= √(2√3) / 2 = (√31) / 2√2
Respond to this Question
Similar Questions

Math
Evaluate *Note  We have to find the exact value of these. That I know to do. For example sin5π/12 will be broken into sin (π/6) + (π/4) So... sin 5π/12 sin (π/6) + (π/4) sin π/6 cos π/4 + cos … 
Math
If α and β are two angles in Quadrant II such that tan α= 1/2 and tan β = 2/3, find cos(α+β) Work: cos(α+β) = [ 1  (tan α)(tan β) ] / [ 1 + (tan α)(tan β)] cos(α+β) … 
Pre Calc
evaluate the trigonometric function of the given quadrantal angle. tan 1400° cos 9π cos 13π/2 sin (17π) 
Precalculus
Use one of the identities cos(t + 2πk) = cos t or sin(t + 2πk) = sin t to evaluate each expression. (Enter your answers in exact form.) (a) sin(19π/4) (b) sin(−19π/4) (c) cos(11π) (d) cos(53π/4) … 
Trig Help!
Question: Trying to find cos π/12, if cos π/6 = square root 3 over 2, how to find cos π/12 using DOUBLE angle formula? 
Trigonometry
IM STUCK ON THESE :( 1. What is the equation for shifting the standard sine curve +2 units horizontally? 
Trigonometry
IM STUCK ON THESE :( 1. What is the equation for shifting the standard sine curve +2 units horizontally? 
trignonmetry
6. Prove that tan λ cos^2 λ + sin^2λ/sin λ = cos λ + sin λ 10. Prove that 1+tanθ/1tanθ = sec^2θ+2tanθ/1tan^2θ 17.Prove that sin^2wcos^2w/tan w sin w + cos w tan w = cos wcot … 
trig help much appreciated! :))
1. Find the complete exact solution of sin x = . 2. Solve cos 2x – 3sin x cos 2x = 0 for the principal value(s) to two decimal places. 3. Solve tan2 x + tan x – 1 = 0 for the principal value(s) to two decimal places. 4. Prove that … 
trigonometry
In questions 2A, 2B, and 2C below, find the exact values using the given information: sin α = 1/6 with α between 0 and π/2 sin β = 3/5 with β between π/2 and π 2A. Find cos (α + β) 2B. Find …