Post a New Question

Prove or disprove?

posted by .

cos(X+pi/6) + sin(x-pi/3) = 0

I am working with one side but I am not sure if I can subtract at all here.

  • Prove or disprove? -

    To see if it is an identity, pick any value of x
    e.g. x = 78°
    then x+π/6 ---> 78+30 = 108°
    and x-π/3 ---> 78 - 60 = 18°

    is cos108 + sin18 = 0 ???
    YES

    ok, then , let's prove it

    LS = cosxcosπ/6 - sinxsinπ/6 + sinxcosπ/3 - cosxsinπ/3
    = √3/2 cosx -1/2 sinx + 1/2 sinx - √3/2 cosx
    = 0
    = RS

  • Prove or disprove? -

    or, since we know that cos(pi/2 - x) = sin(x)

    cos(pi/2 - (x+pi/6)) = sin(pi/3 - x) = -sin(x-pi/3)

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. math

    Prove that for all real values of a, b, t (theta): (a * cos t + b * sin t)^2 <= a^2 + b^2 I will be happy to critique your work. Start on the left, square it, (a * cos t + b * sin t)^2 = a^2 (1 - sin^2t) + 2ab sin t cost+ b^2 (1 …
  2. trig

    it says to verify the following identity, working only on one side: cotx+tanx=cscx*secx Work the left side. cot x + tan x = cos x/sin x + sin x/cos x = (cos^2 x +sin^2x)/(sin x cos x) = 1/(sin x cos x) = 1/sin x * 1/cos x You're almost …
  3. Mathematics - Trigonometric Identities

    Let y represent theta Prove: 1 + 1/tan^2y = 1/sin^2y My Answer: LS: = 1 + 1/tan^2y = (sin^2y + cos^2y) + 1 /(sin^2y/cos^2y) = (sin^2y + cos^2y) + 1 x (cos^2y/sin^2y) = (sin^2y + cos^2y) + (sin^2y + cos^2y) (cos^2y/sin^2y) = (sin^2y …
  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 + cos^6 …
  5. Precalc

    Prove or disprove the following identity. cos(-x) - sin(-x) = cos(x) + sin(x)
  6. Prove or Disprove

    Cos(X+y)cos(x-y)= cos^2theta - sin^2theta I foiled the left side as a start because I can kind of see sin^2+cos^2=1 but I can't finish.
  7. Precalculus with Trigonometry

    Prove or disprove the following identity: (sin(10x))/(sin(x)+sin(9x)) = (cos(5x))/(cos4x))
  8. Precalculus with Trigonometry

    Prove or disprove the following Identities: cos(-x) - sin(-x) = cos(x) + sin (x) sin raised to the 4 (theta) - cos raised to the 4 (theta) = sin squared (theta) - cos squared (theta) cos (x+(pi)/(6)) + sin (x - (pi)/(3)) = 0 cos(x+y)cos(x-y) …
  9. Trigonometry desperate help, clueless girl here

    2. solve cos 2x-3sin x cos 2x=0 for the principal values to two decimal places. 3. solve tan^2 + tan x-1= 0 for the principal values to two decimal places. 4. Prove that tan^2(x) -1 + cos^2(x) = tan^2(x) sin^2 (x). 5.Prove that tan(x) …
  10. MATH

    Hi, I really need help with these questions. I did some of them halfway, but then I got stuck. Would you please help me?

More Similar Questions

Post a New Question