Math Problem Statement

Suppose csc(A) = -13/5 where A terminates in QIV, and sec(B) = -2 where B terminates in QII. First, determine sin(A), cos(A), tan(A), sin(B), cos(B), and tan(B).

Solution

Let’s solve the given problem step by step.

Given Information:

  1. For angle AA:

    • csc(A)=135\csc(A) = -\frac{13}{5} (AA is in Quadrant IV).
    • Therefore, sin(A)=513\sin(A) = \frac{-5}{13} (reciprocal of csc(A)\csc(A)).
  2. For angle BB:

    • sec(B)=2\sec(B) = -2 (BB is in Quadrant II).
    • Therefore, cos(B)=12\cos(B) = -\frac{1}{2} (reciprocal of sec(B)\sec(B)).

Step 1: Solve for cos(A)\cos(A) and tan(A)\tan(A):

Using the Pythagorean identity: sin2(A)+cos2(A)=1\sin^2(A) + \cos^2(A) = 1 (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)=144169\cos^2(A) = \frac{144}{169} cos(A)=±1213\cos(A) = \pm \frac{12}{13} Since AA is in Quadrant IV, cos(A)>0\cos(A) > 0: cos(A)=1213\cos(A) = \frac{12}{13}

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


Step 2: Solve for sin(B)\sin(B) and tan(B)\tan(B):

Using the Pythagorean identity: sin2(B)+cos2(B)=1\sin^2(B) + \cos^2(B) = 1 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)=34\sin^2(B) = \frac{3}{4} sin(B)=±34=±32\sin(B) = \pm \sqrt{\frac{3}{4}} = \pm \frac{\sqrt{3}}{2} Since BB is in Quadrant II, sin(B)>0\sin(B) > 0: sin(B)=32\sin(B) = \frac{\sqrt{3}}{2}

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


Final Results:

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

Let me know if you'd like a detailed explanation for any part or help with other aspects of this problem!


Additional Questions to Explore:

  1. How do the signs of trigonometric functions differ across quadrants?
  2. What is the reciprocal identity relationship between csc\csc, sec\sec, and tan\tan?
  3. How would the solution change if the given quadrants were different?
  4. Can we verify these results using the unit circle?
  5. How do these values translate to real-world applications of trigonometry?

Tip:

Always use the Pythagorean identities and the quadrant-specific signs to verify trigonometric values.

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Math Problem Analysis

Mathematical Concepts

Trigonometric Identities
Pythagorean Theorem
Reciprocal Functions
Quadrant Analysis

Formulas

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

Theorems

Pythagorean Identity

Suitable Grade Level

Grades 10-12