Math Problem Statement

Write sin(t) in terms of sec(t) if the terminal point determined by t is in Quadrant IV.

Solution

The problem requires expressing sin(t)\sin(t) in terms of sec(t)\sec(t) given that the angle tt is in the fourth quadrant.

Step-by-Step Solution:

  1. Recall Trigonometric Identities: We know the identity: sin2(t)+cos2(t)=1\sin^2(t) + \cos^2(t) = 1 Since sec(t)=1cos(t)\sec(t) = \frac{1}{\cos(t)}, we can express cos(t)\cos(t) in terms of sec(t)\sec(t): cos(t)=1sec(t)\cos(t) = \frac{1}{\sec(t)}

  2. Rewrite sin2(t)\sin^2(t): Substitute cos(t)\cos(t) in the identity: sin2(t)=1cos2(t)=1(1sec(t))2\sin^2(t) = 1 - \cos^2(t) = 1 - \left(\frac{1}{\sec(t)}\right)^2 Simplify further: sin2(t)=11sec2(t)=sec2(t)1sec2(t)\sin^2(t) = 1 - \frac{1}{\sec^2(t)} = \frac{\sec^2(t) - 1}{\sec^2(t)}

  3. Take the Square Root: To find sin(t)\sin(t), take the square root of both sides: sin(t)=±sec2(t)1sec2(t)\sin(t) = \pm \sqrt{\frac{\sec^2(t) - 1}{\sec^2(t)}} Simplify by expressing in terms of sec(t)\sec(t): sin(t)=±sec2(t)1sec(t)\sin(t) = \pm \frac{\sqrt{\sec^2(t) - 1}}{\sec(t)}

  4. Determine the Sign in the Fourth Quadrant: In the fourth quadrant, sin(t)\sin(t) is negative. Therefore: sin(t)=sec2(t)1sec(t)\sin(t) = -\frac{\sqrt{\sec^2(t) - 1}}{\sec(t)}

Final Answer:

sin(t)=sec2(t)1sec(t)\sin(t) = -\frac{\sqrt{\sec^2(t) - 1}}{\sec(t)}

Would you like a more detailed explanation, or do you have any questions?

Further Questions to Explore

  1. How would you express cos(t)\cos(t) in terms of csc(t)\csc(t) in a different quadrant?
  2. What happens if tt is in the first quadrant? How does the expression change?
  3. Can you derive a similar expression for tan(t)\tan(t) in terms of sec(t)\sec(t)?
  4. Why does the sign of sin(t)\sin(t) change in different quadrants?
  5. How does knowing the quadrant simplify solving trigonometric expressions?

Tip

When working with trigonometric identities in specific quadrants, always check the sign of the function based on the quadrant to avoid mistakes.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Trigonometric Identities
Quadrants

Formulas

Pythagorean identity: sin^2(t) + cos^2(t) = 1
sec(t) = 1/cos(t)

Theorems

Pythagorean Identity

Suitable Grade Level

Grades 10-12