Math III

For a particular angle theta, the cosine function f(x) = a cos b(theta) has the following values within one cycle of the function: f(0)=4;f(pi/4)=0;f(pi/2)=-4;f(3pi/4)=0;f(pi)=4. What is the rule for the cosine function?
a. y=2cos4theta
b. y=4cos2theta
c. y=-4cos3theta
d. y=1/4cos2theta

  1. 👍 0
  2. 👎 0
  3. 👁 1,265
  1. huh? Just work with the numbers:
    a cos b(theta)
    has the following values within one cycle of the function: f(0)=4;f(pi/4)=0;f(pi/2)=-4;f(3pi/4)=0;f(pi)=4

    acos(b*0) = 4
    so, a=4

    4cos(b*pi/2) = -4,
    so, b*pi/2 = pi
    b = 2

    f(θ) = 4cos(2θ)

    1. 👍 3
    2. 👎 1
  2. Thanks steve!

    1. 👍 1
    2. 👎 0

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. Precalculus

    Circle O below has radius 1. Eight segment lengths are labeled with lowercase letters. Six of these equal a trigonometric function of theta. Your answer to this problem should be a six letter sequence whose letters represent the

    asked by Human on September 24, 2016
  3. Precalculus

    Which of the following are trigonometric identities? Select all that apply (there are 3 answers). A cos^2(theta)=sin^2(theta)-1 B sin(theta)=1/csc(theta) C sec(theta)=1/cot(theta) D cot(theta)=cos/sin(theta) E

    asked by Statten on March 6, 2018
  4. Algebra 2

    Which cosine function has maximum of 4, a minimum of -4, and a period of 2pi/3? A. y=4 cos 3 theta B. y= 4 cos 2 theta/3 C. y=4 cos theta/3 D. y=4 cos 3 theta

    asked by Caleb on May 25, 2014
  5. Algebra2

    The function f(theta) and g (theta) are sine functions where f(0)=g(0)=0. The amplitude of f (theta) is twice the amplitude of g(theta). The period of f(theta) is one-half the period of g(theta). If g (theta) has a period of 2pi

    asked by steve on May 11, 2017
  1. Pre-Calculus

    1.) Which of the following polar equations is equivalent to the parametric equations below? x=t^2 y=2t A.) r=4cot(theta)csc(theta) B.) r=4tan(theta)sec(theta) C.) r=tan(theta)sec(theta)/4 D.) r=16cot(theta)csc(theta) 2.) Which

    asked by line on May 18, 2018
  2. Pre-Calculus

    Which is the polar form of the parametric equations x=5cos(theta) and y=5sin(theta) ? a. r= 5(theta) b. r= 5 c. r= 25 cos (theta) sin (theta)***** d. r= 25cos^2 (theta) + 25sin^2 (theta) Which is the polar form of the parametric

    asked by Vsuf on May 22, 2018
  3. Precalculus check answers help!

    1.) Find an expression equivalent to sec theta sin theta cot theta csc theta. tan theta csc theta sec theta ~ sin theta 2.) Find an expression equivalent to cos theta/sin theta . tan theta cot theta ~ sec theta csc theta 3.)

    asked by Kelsey on May 30, 2012
  4. trig

    Let (theta) be an angle in quadrant II such that csc(theta)=8/5 Find the exact value of tan(theta) and cos(theta).

    asked by andy on May 10, 2011
  5. trig

    Find csc(theta), tan (theta), and cos (theta), where theta is the angle shown in the figure. Give exact values, not decimal approximations c=10 b=7 a=7.14 the right angle is locate between sides a and b and the theta angle is an

    asked by Joey on March 24, 2014

You can view more similar questions or ask a new question.