Math Problem Statement

Given cotangent, A, equals, minus, start fraction, 5, divided by, 4, end fractioncotA=−45​ and that angle AA is in Quadrant IV, find the exact value of cosecant, AcscA in simplest radical form using a rational denominator.

Solution

To find the exact value of cscA\csc A given cotA=54\cot A = -\frac{5}{4} with angle AA in Quadrant IV, follow these steps:

  1. Set up the right triangle based on cotA\cot A:

    • Since cotA=54\cot A = -\frac{5}{4}, we know that cotA=adjacentopposite\cot A = \frac{\text{adjacent}}{\text{opposite}}.
    • In this case, the adjacent side is 55 and the opposite side is 4-4 (negative because we are in Quadrant IV, where sine values are negative).
  2. Use the Pythagorean theorem to find the hypotenuse: hypotenuse=(opposite)2+(adjacent)2\text{hypotenuse} = \sqrt{(\text{opposite})^2 + (\text{adjacent})^2} Substituting in the values: hypotenuse=(4)2+52=16+25=41\text{hypotenuse} = \sqrt{(-4)^2 + 5^2} = \sqrt{16 + 25} = \sqrt{41}

  3. Determine cscA\csc A:

    • cscA=hypotenuseopposite\csc A = \frac{\text{hypotenuse}}{\text{opposite}}.
    • Substituting the values, we get: cscA=414=414\csc A = \frac{\sqrt{41}}{-4} = -\frac{\sqrt{41}}{4}

So, the exact value of cscA\csc A in simplest radical form with a rational denominator is: cscA=414\csc A = -\frac{\sqrt{41}}{4}

Would you like a breakdown of any part of this solution?

Here are 5 related questions:

  1. How would you find secA\sec A given cotA=54\cot A = -\frac{5}{4} and AA in Quadrant IV?
  2. What is the value of sinA\sin A for the same conditions?
  3. How does knowing the quadrant affect the sign of trigonometric functions?
  4. How can you verify that this solution is correct using another trigonometric identity?
  5. How would the answer change if AA were in Quadrant II?

Tip: In trigonometry, always pay close attention to the quadrant, as it determines the sign of the function values.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Cotangent
Cosecant
Pythagorean Theorem

Formulas

cot A = adjacent / opposite
csc A = hypotenuse / opposite
Pythagorean Theorem: hypotenuse^2 = adjacent^2 + opposite^2

Theorems

Pythagorean Theorem

Suitable Grade Level

Grades 9-11