Math Problem Statement

State all angles between 0° and 360° that make each statement true: a) sin 200° = sin _____ b) tan θ = -2.747, therefore θ = _____ or _____ c) cos 135° = -cos _____ or _____ d) tan (-100°) = tan _____ or _____

Solution

To solve these problems, we need to use trigonometric identities and properties of angles in different quadrants. Let's go through each part systematically.

Problem Analysis and Solutions:

  1. State all angles between 00^\circ and 360360^\circ that make each statement true:

    a) sin200=sin   \sin 200^\circ = \sin \underline{\ \ \ }

    • To find the other angle with the same sine value, we use the fact that sine is positive in the first and second quadrants and negative in the third and fourth quadrants.
    • The reference angle for 200200^\circ is 200180=20200^\circ - 180^\circ = 20^\circ.
    • So, the other angle with the same sine is 360200=160360^\circ - 200^\circ = 160^\circ.
    • Answer: sin200=sin160\sin 200^\circ = \sin 160^\circ.

    b) tanθ=2.747θ=     or     \tan \theta = -2.747 \Rightarrow \theta = \underline{\ \ \ \ } \text{ or } \underline{\ \ \ \ }

    • Tangent is negative in the second and fourth quadrants.
    • Using the arctangent of 2.7472.747, we find the reference angle as tan1(2.747)70\tan^{-1}(2.747) \approx 70^\circ.
    • The solutions in the given range are:
      • 18070=110180^\circ - 70^\circ = 110^\circ (second quadrant).
      • 36070=290360^\circ - 70^\circ = 290^\circ (fourth quadrant).
    • Answer: θ=110\theta = 110^\circ or θ=290\theta = 290^\circ.

    c) cos135=cos     or     \cos 135^\circ = -\cos \underline{\ \ \ \ } \text{ or } \underline{\ \ \ \ }

    • The angle 135135^\circ is in the second quadrant, where cosine is negative.
    • We want an angle with the same reference angle where cosine is positive.
    • The reference angle for 135135^\circ is 13590=45135^\circ - 90^\circ = 45^\circ.
    • The other angles where cosine has the same magnitude but is positive are:
      • 4545^\circ and 36045=315360^\circ - 45^\circ = 315^\circ.
    • Answer: cos135=cos45\cos 135^\circ = -\cos 45^\circ or cos315-\cos 315^\circ.

    d) tan(100)=tan     or     \tan(-100^\circ) = \tan \underline{\ \ \ \ } \text{ or } \underline{\ \ \ \ }

    • To find an equivalent positive angle for 100-100^\circ, add 360360^\circ:
      • 100+360=260-100^\circ + 360^\circ = 260^\circ.
    • The other angle with the same tangent value in the given range is:
      • 180+80=80180^\circ + 80^\circ = 80^\circ.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Reference Angles
Quadrants

Formulas

sin(θ) = sin(180° - θ) or sin(θ) = sin(360° - θ)
tan(θ) is negative in the 2nd and 4th quadrants
cos(θ) = cos(180° - θ) or cos(θ) = cos(360° - θ)

Theorems

Trigonometric identities for sine, cosine, and tangent in different quadrants

Suitable Grade Level

Grades 10-12