PRECALC
posted by help! .
solve the equation
1. cos(θ) − sin(θ) = 1
2.2 cos(θ) tan(θ) + tan(θ) = 1 + 2 cos(θ)
3. sin(θ) cos(3θ) + cos(θ) sin(3θ) = 0
4. sin(2θ) cos(θ) − cos(2θ) sin(θ) = 1/2
5. cos(2θ) + cos(θ) = 2
6. cos(2θ) + sin2(θ) = 0

PRECALC 
Reiny
#1, look how I did this similar problem, and follow the same steps
http://www.jiskha.com/display.cgi?id=1461697741
#2
2 cos(θ) tan(θ) + tan(θ) = 1 + 2 cos(θ)
2cosθtanθ  2cos + tanθ  1 = 0
2cosθ(tanθ  1) + (tanθ 1) = 0
by grouping:
(tan  1)(2cosθ + 1) = 0
tanθ = 1 or cosθ = 1/2
θ = 45 or θ = 225 or θ = 240 or θ =300 degrees
in radians: θ = π/4, 5π/4, 4π/3, 5π/3
#3 and #4 are based on the formula
sin(A ± B) = sinAcosB ± cosAsinB
I will do #4, you do #3
sin(2θ) cos(θ) − cos(2θ) sin(θ) = 1/2
sin(2θ  θ) = 1/2
sin θ = 1/2
θ = 30 degrees or θ = 150 degrees
or θ = pi/6 or 5pi/6
#5
I will assume you mean:
cos(2θ) + sin^2 (θ) = 0
cos^2 θ  sin^2 θ + sin^2 θ = 0
cos^2 θ = 0
cosθ = 0
θ = 90 or θ = 270 degrees
θ = pi/2 or 3pi/2
Respond to this Question
Similar Questions

Math  Calculus
The identity below is significant because it relates 3 different kinds of products: a cross product and a dot product of 2 vectors on the left side, and the product of 2 real numbers on the right side. Prove the identity below.  a … 
math
if cosθ=2/3 and tanθ<0 find the exact value sin(θ5π/3) sin2θ cos2θ cos(θ/2) can some1 please help me? 
trigonometry
if cosθ=2/3 and tanθ<0 find the exact value sin(θ5π/3) sin2θ cos2θ cos(θ/2) can some1 please help me? 
Trigonometry
Which of the following is equivalent to 1 − cos 2 θ/cos 2 θ? 
Calculus AP
hi again im really need help TextBook: James Stewart:Essential Calculus, page 311. Here the problem #27: First make a substitution and then use integration by parts to evaluate the integral. Integral from sqrt(pi/2) TO sqrt(pi)of θ^3 … 
Trigonometry
1.Solve tan^2x + tan x – 1 = 0 for the principal value(s) to two decimal places. 6.Prove that tan y cos^2 y + sin^2y/sin y = cos y + sin y 10.Prove that 1+tanθ/1tanθ = sec^2θ+2tanθ/1tan^2θ 17.Prove that … 
Trigonometry
There are four complex fourth roots to the number 4−4√3i. These can be expressed in polar form as z1=r1(cosθ1+isinθ1) z2=r2(cosθ2+isinθ2) z3=r3(cosθ3+isinθ3) z4=r4(cosθ4+isinθ4), … 
Complex angles
There are four complex fourth roots to the number 4−43√i. These can be expressed in polar form as z1=r1(cosθ1+isinθ1) z2=r2(cosθ2+isinθ2) z3=r3(cosθ3+isinθ3) z4=r4(cosθ4+isinθ4), … 
Math Question
Given tan θ = 8/5 and sin θ < 0, find sin θ, cos θ, csc θ, sec θ, and cot θ. 
Calculusantiderivative
Find f. f ''(θ) = sin θ + cos θ, f(0) = 5, f '(0) = 3 My steps: f'(θ)=cosθsinθ+C When f'(0)=3, C=2, so f'(θ)=cosθsinθ2. f(θ)=sinθcosθ2x+D When f(0)=5, D=6, so f is …