Pre-Calculus

Find two exact values of theta in degrees (0 less than or equal to theta < 360°) if cos theta = -(square root of 2)/2.

  1. 👍 0
  2. 👎 0
  3. 👁 92
asked by Sade
  1. cosØ = -√2/2
    so Ø is in quadrants II or III

    you should know the trig ratios of the 45-45-90 as well as the 30-60-90 degree triangles.
    so you know the angle in standard position is 45°, because cos45 = √2/2

    so Ø = 180-45 or 135° (in II)
    or Ø = 180+45 = 225° (in III)

    1. 👍 0
    2. 👎 0
    posted by Reiny

Respond to this Question

First Name

Your Response

Similar Questions

  1. Math

    1. Let (-7, 4) be a point on the terminal side of (theta). Find the exact values of sin(theta), csc(theta), and cot(theta). 2. Let (theta) be an angle in quadrant IV such that sin(theta)=-2/5. Find the exact values of sec(theta)

    asked by Kandee Johnson on May 15, 2011
  2. Mathematics

    1. Show that Sin3 Theta - Cos2 Theta = (1 - Sin Theta)(4Sin^2 Theta + 2Sin Theta - 1). Without using a calculator, show that Theta = 18 degrees is an exact solution of the equation Sin3 Theta = Cos2 Theta. Justifying your answer,

    asked by Edwards on August 3, 2011
  3. Algebra II

    Multiple Choice (theta) means the symbol 0 with the dash in it. 1.)Which expression is equivalent to tan(theta)-(sec(theta))/(sin(theta))? A.)-cot(theta) B.)cot(theta) C.)tan(theta)-cot(theta) D.)tan(theta)-sec^2(theta) 2.)Find

    asked by HotMath on June 9, 2011
  4. Calc

    Calculate the exact values of sin(theta) cos(theta) and tan (theta) when theta=240 degrees. How would I do this with and without a calculator?

    asked by Jillian on December 9, 2011
  5. Pre Cal

    2cos 4theta + 1 = 0 i know how to find the degrees (the last step of the problem), but i don't know how to start the problem. Could someone please show me the steps? I assume you mean cos (4 theta) and not (cos theta)^4 cos (4

    asked by Marie on March 7, 2007
  6. 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

    asked by Leeroy on November 7, 2014
  7. Math Trig Please Help!!!

    Find exact values for all the solutions to the equation cos theta = sqrt 3/2 for -2pi

    asked by George on November 7, 2014
  8. trig

    find two values of theta, zero degrees is than or equal to theta which is less than 360 degrees, that satisfy the given trigonometric equation. tan theta equals radical 3.

    asked by damion on January 25, 2012
  9. Math

    Let (7,-3) be a point on the terminal side of theta. Find the exact values of sin of theta, csc of theta and cot of theta?

    asked by Justin on November 29, 2016
  10. Trig

    suppose that the angle theta is in the second quadrant, and that sin(theta)=1/3. Find exact values for cos (theta) and csc (theta)

    asked by alicia otto on April 5, 2016

More Similar Questions