Post a New Question

math

posted by .

how would you determine a formula for cot(2x) using only cot(x)? Thenhow would you determine a formula for sec(2x) using only sec(x)?

  • math -

    cot 2x = 1/tan 2x
    = 1/[2tanx/(1-tan^2(x))]
    = (1-tan^2(x))/2tanx
    = [1 - 1/cot^2(x))/(2/cotx)
    = [(cot^2(x) - 1)/cot^2(x)]/[2/cotx]
    = (cot^2(x) - 1)/(2cotx)

    I don't know if that is the simplest way, I just sort of followed by nose.

    you can try sec 2x by noting
    sec 2x = 1/cos 2c
    then using cos2x = 2cos^2(x) - 1

    follow the above procedure.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. math

    when you are determining a formula for cot(2x) using only tan(x) would the formula be...(1-tan^2(x))/(2tan(x))?
  2. MATH

    Determine a formula for sec(2è) using both sec(è) and csc(è). Determine a formula for csc(2è) using both sec(è) and csc(è).
  3. Math - Trig

    I'm trying to verify these trigonometric identities. 1. 1 / [sec(x) * tan(x)] = csc(x) - sin(x) 2. csc(x) - sin(x) = cos(x) * cot(x) 3. 1/tan(x) + 1/cot(x) = tan(x) + cot(x) 4. csc(-x)/sec(-x) = -cot(x)
  4. Math - Trigonometry

    Verify the following: 1. cos x/(1-sinx)= sec x + tan x 2. (tanx+1)^2=sec^2x + 2tan x 3. csc x = )cot x + tan x)/sec x 4. sin2x - cot x = -cotxcos2x
  5. math

    Determine the values of sin, cos, tan, csc, sec and cot at (-3, -3) on the terminal arm of an angle in standard position 2. If cos θ = 2/3 and 270° < θ < 360° then determine the exact value of 1/cot
  6. trigonometry repost

    Reduce (csc^2 x - sec^2 X) to an expression containing only tan x. (is this correct?
  7. trig

    For each expression in column I, choose the expression from column II to complete an identity: Column I Column II 1. -tanxcosx A. sin^2x/cos^2x 2. sec^2x-1 B. 1/sec^2x 3. sec x/cscx C. sin(-x) 4. 1+sin^2x D.csc^2x-cot^2x+sin^2x 5. …
  8. Math/Trig

    How would I evaluate these trig functions without using a calculator?
  9. math

    Determine all the possible values of x where 0 deg is more than or equal to x and x is more or equal to 360 deg such that i'm not sure the solution, please correct it and how to find the x value, 2 tan x - 1 = cot x solution: (sec …
  10. Trig verifying identities

    I am having trouble with this problem. sec^2(pi/2-x)-1= cot ^2x I got : By cofunction identity sec(90 degrees - x) = csc x secx csc-1 = cot^2x Then split sec x and csc-1 into two fractions and multiplied both numerator and denominators …

More Similar Questions

Post a New Question