Math Problem Statement

Suppose csc(A) = -13/5 where A terminates in Quadrant IV, and sec(B) = -2 where B terminates in Quadrant II. Determine sin(A), cos(A), tan(A), sin(B), cos(B), and tan(B).

Solution

Let’s solve this problem step-by-step based on the given details:

Problem Breakdown:

  1. For AA: We are told that:

    • csc(A)=135\csc(A) = -\frac{13}{5}, which means sin(A)=513\sin(A) = -\frac{5}{13} (since csc\csc is the reciprocal of sin\sin).
    • AA terminates in Quadrant IV, where cos(A)>0\cos(A) > 0 and sin(A)<0\sin(A) < 0.

    Using the Pythagorean Identity: sin2(A)+cos2(A)=1\sin^2(A) + \cos^2(A) = 1 Substituting sin(A)=513\sin(A) = -\frac{5}{13}: (513)2+cos2(A)=1\left(-\frac{5}{13}\right)^2 + \cos^2(A) = 1 25169+cos2(A)=1\frac{25}{169} + \cos^2(A) = 1 cos2(A)=125169=144169\cos^2(A) = 1 - \frac{25}{169} = \frac{144}{169} cos(A)=144169=1213(positive in Quadrant IV)\cos(A) = \sqrt{\frac{144}{169}} = \frac{12}{13} \quad (\text{positive in Quadrant IV})

    Now, tan(A)=sin(A)cos(A)\tan(A) = \frac{\sin(A)}{\cos(A)}: tan(A)=5131213=512\tan(A) = \frac{-\frac{5}{13}}{\frac{12}{13}} = -\frac{5}{12}

    Summary for AA:

    • sin(A)=513\sin(A) = -\frac{5}{13}
    • cos(A)=1213\cos(A) = \frac{12}{13}
    • tan(A)=512\tan(A) = -\frac{5}{12}
  2. For BB: We are told that:

    • sec(B)=2\sec(B) = -2, which means cos(B)=12\cos(B) = -\frac{1}{2} (since sec\sec is the reciprocal of cos\cos).
    • BB terminates in Quadrant II, where sin(B)>0\sin(B) > 0 and cos(B)<0\cos(B) < 0.

    Using the Pythagorean Identity: sin2(B)+cos2(B)=1\sin^2(B) + \cos^2(B) = 1 Substituting cos(B)=12\cos(B) = -\frac{1}{2}: sin2(B)+(12)2=1\sin^2(B) + \left(-\frac{1}{2}\right)^2 = 1 sin2(B)+14=1\sin^2(B) + \frac{1}{4} = 1 sin2(B)=114=34\sin^2(B) = 1 - \frac{1}{4} = \frac{3}{4} sin(B)=34=32(positive in Quadrant II)\sin(B) = \sqrt{\frac{3}{4}} = \frac{\sqrt{3}}{2} \quad (\text{positive in Quadrant II})

    Now, tan(B)=sin(B)cos(B)\tan(B) = \frac{\sin(B)}{\cos(B)}: tan(B)=3212=3\tan(B) = \frac{\frac{\sqrt{3}}{2}}{-\frac{1}{2}} = -\sqrt{3}

    Summary for BB:

    • sin(B)=32\sin(B) = \frac{\sqrt{3}}{2}
    • cos(B)=12\cos(B) = -\frac{1}{2}
    • tan(B)=3\tan(B) = -\sqrt{3}

Completed Table:

Value
sin(A)\sin(A)513-\frac{5}{13}
cos(A)\cos(A)1213\frac{12}{13}
tan(A)\tan(A)512-\frac{5}{12}
sin(B)\sin(B)32\frac{\sqrt{3}}{2}
cos(B)\cos(B)12-\frac{1}{2}
tan(B)\tan(B)3-\sqrt{3}

Would you like a detailed explanation of any specific part or more problems like this?

Relative Questions:

  1. How do we calculate the other trigonometric functions if only one is given?
  2. Why does the quadrant affect the sign of the trigonometric values?
  3. What is the relationship between sec\sec and cos\cos, or csc\csc and sin\sin?
  4. How does the Pythagorean Identity help in finding missing values?
  5. How do we determine the quadrant of the angle using trigonometric signs?

Tip: Always consider the quadrant to correctly

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Math Problem Analysis

Mathematical Concepts

Trigonometric Identities
Quadrant Analysis
Pythagorean Theorem

Formulas

sin^2(x) + cos^2(x) = 1
csc(x) = 1/sin(x)
sec(x) = 1/cos(x)
tan(x) = sin(x)/cos(x)

Theorems

Pythagorean Identity

Suitable Grade Level

Grades 10-12