math (trig)

posted by .

if cos 2 theta = -(1/3) and theta is in Quadrant 2, find sin theta, cos theta, tan theta, and draw triangle theta

  • math (trig) -

    -1/3 = cos 2theta = 1 - 2 sin^2 theta
    2 sin^2 theta = 4/3
    sin theta = sqrt(2/3)
    cos theta = sqrt(1 - 2/3) = -sqrt(1/3)
    (minus since theta must be in quadrant 2)

    tan theta = -sqrt2

    theta = 125.26 degrees

    You draw the figure

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Calculus

    I wanted to confirm that I solved these problems correctly (we had to convert the polar curves to Cartesian equations). 1.rcos(theta)=1 x=1 2.r=2*sin(theta)+2*cos(theta) r^2=2rsin(theta)+2rcos(theta) x^2+y^2=2y+2x (a little unsure …
  2. trig

    If sin 2 theta = (2/5) in Quadrant 2, find sin theta, cos theta, tan theta, and draw triangle theta.
  3. Algebra II

    Multiple Choice Which expression is NOT equivalent to 1?
  4. precalc h

    sin(theta)/1-cos(theta) + 1-cos(theta)/sin(theta) = 2csc(theta) That question makes absolutely no sense.. could someone help me?
  5. trig

    If sin theta is equal to 5/13 and theta is an angle in quadrant II find the value of cos theta, sec theta, tan theta, csc theta, cot theta.
  6. math

    I have a question I have been working on since yesterday and I am not making this up. I couldn't get the right answer. If sin theta = -2/3, which of the following are possible?
  7. Math Trig Help

    sin theta = x/3, with theta in the first quadrant, find the expression for cos theta and tan theta. Answers will be in algebraic terms of x. Give exact answers with 0 < theta <pi/2 (0 less than or equal to theta, less than or …
  8. Trigonometry

    Prove the following identities: 1. (tan theta - sin theta)^2 + (1-cos theta)^2 = (1-sec theta) ^2 2. (1-2cos^2 theta) / sin theta cos theta = tan theta - cot theta 3. (sin theta + cos theta ) ^2 + (sin theta - cos theta ) ^2 = 2 Thank …
  9. Trigonometry

    Prove the following identities: 1. (tan theta - sin theta)^2 + (1-cos theta)^2 = (1-sec theta) ^2 2. (1-2cos^2 theta) / sin theta cos theta = tan theta - cot theta 3. (sin theta + cos theta ) ^2 + (sin theta - cos theta ) ^2 = 2 Thank …
  10. Calculus

    If cos of theta= -7/12 and theta is in quadrant 2 then find a. tan(theta) cot (theta)= b. csc(theta) tan(theta)= c. sin^2(theta)+ cos^2(theta)=

More Similar Questions