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 tan2  – 1 + cos2  = tan2  sin2 .
5. Prove that tan  sin  + cos  = sec .
6. Prove that = cos  + sin .
7. Prove that .
8. Prove that = cos  – cot  cos .
9. Find a counterexample to shows that the equation sec  – cos  = sin  sec  is not
an identity.
sin cos
tan sin cos tan
2 2 ω ω
ωω ω ω

+
1 + tan
1 tan
sec + 2tan
1 tan
2
2
θ
θ
θ θ
− − θ
=
tan cos + sin
sin

10. Write tan as a function of  only.
11. Write cos as a function of  only.
12. Write cos(–83°) as a function of a positive angle.
13. Write sin(125°) in terms of its cofunction. Make sure your answer is a function
of a positive angle.
14. Find the exact value of sin(195°).

asked by suzy
  1. no ideas on any of these? Also you have some major typos and/or formatting issues.

    I'll do a couple. Maybe you can clean up the post and indicate where you get stuck on the others.

    #2
    cos 2x – 3sin x cos 2x = 0
    (1-3sinx)cos2x = 0
    so, either
    cos2x=0 ==> x = pi/4 or 3pi/4
    sinx = 1/3 ==> x=arcsin(1/3) or pi-arcsin(1/3)

    #3
    tan2 x + tan x – 1 = 0
    tanx = (-1±√5)/2
    so find arctan of those two values and recall that tan is positive in QI,QIII and negative in QII,QIV

    posted by Steve
  2. alright, I will. Thanks

    posted by Suzy

Respond to this Question

First Name

Your Response

Similar Questions

  1. MATH

    1.)Find the exact solution algebriacally, if possible: (PLEASE SHOW ALL STEPS) sin 2x - sin x = 0 2.) GIVEN: sin u = 3/5, 0 < u < ï/2 Find the exact values of: sin 2u, cos 2u and tan 2u using the double-angle formulas.
  2. trigonometry

    5.Find the complete exact solution of sin x = -√3/2. 10. Solve cos 2x – 3sin x cos 2x = 0 for the principal value(s) to two decimal places. 12. Solve tan^2x + tan x – 1 = 0 for the principal value(s) to two decimal
  3. trigonometry

    5. Find the complete exact solution of sin x = -√3/2. 9. Solve cos 2x – 3sin x cos 2x = 0 for the principal value(s) to two decimal places. 21. Solve tan^2x + tan x – 1 = 0 for the principal value(s) to two decimal
  4. TRIG!

    Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6 x=1 - (3/4)sin^2 2x work on one side only! Responses Trig please help! - Reiny, Monday, February 23, 2009 at 4:27pm LS looks like the sum of cubes sin^6 x +
  5. Trig hep, please? Thank you!

    1. Find the exact value of sin(195(degrees)) 2. If cot2(delta)=5/12 with 0(<or =)2(delta)pi, find cos(delta), sin(delta) , tan(delta). 3.find the exact value of sin2(x) if cos(x)= 4/5. (X is in quadrant 1) 4. Find the exact
  6. Calculus 12th grade (double check my work please)

    1.)Find dy/dx when y= Ln (sinh 2x) my answer >> 2coth 2x. 2.)Find dy/dx when sinh 3y=cos 2x A.-2 sin 2x B.-2 sin 2x / sinh 3y C.-2/3tan (2x/3y) D.-2sin2x / 3 cosh 3yz...>> my answer. 2).Find the derivative of
  7. Trigonometry

    4. Find the exact value for sin(x+y) if sinx=-4/5 and cos y = 15/17. Angles x and y are in the fourth quadrant. 5. Find the exact value for cos 165degrees using the half-angle identity. 1. Solve: 2 cos^2x - 3 cosx + 1 = 0 for 0
  8. math

    Use the exact values of the sin, cos and tan of pi/3 and pi/6, and the symmetry of the graphs of sin, cos and tan, to find the exact values of si -pi/6, cos 5/3pi and tan 4pi/3. I have found the answers to the first three using
  9. tigonometry

    expres the following as sums and differences of sines or cosines cos8t * sin2t sin(a+b) = sin(a)cos(b) + cos(a)sin(b) replacing by by -b and using that cos(-b)= cos(b) sin(-b)= -sin(b) gives: sin(a-b) = sin(a)cos(b) - cos(a)sin(b)
  10. Math- Trig

    1. Determine the exact value of cos^-1 (pi/2). Give number and explanaton. 2. Determine the exact value of tan^-1(sq. root 3). with explanation. 3. Determine exact value of cos(cos^-1(19 pi)). with explanation. 4. Determine the

More Similar Questions