Math Problem Statement

Simplify sin(t) / (sec(t) - cos(t)) to a single trig function with no fractions.

Solution

We need to simplify the given expression:

sin(t)sec(t)cos(t)\frac{\sin(t)}{\sec(t) - \cos(t)}

to a single trigonometric function with no fractions.


Step 1: Rewrite sec(t)\sec(t) using its definition

Recall that sec(t)=1cos(t)\sec(t) = \frac{1}{\cos(t)}. Substituting into the denominator:

sin(t)sec(t)cos(t)=sin(t)1cos(t)cos(t).\frac{\sin(t)}{\sec(t) - \cos(t)} = \frac{\sin(t)}{\frac{1}{\cos(t)} - \cos(t)}.


Step 2: Combine terms in the denominator

To combine terms in the denominator, find a common denominator for 1cos(t)\frac{1}{\cos(t)} and cos(t)\cos(t):

1cos(t)cos(t)=1cos2(t)cos(t).\frac{1}{\cos(t)} - \cos(t) = \frac{1 - \cos^2(t)}{\cos(t)}.


Step 3: Recognize a Pythagorean identity

From the Pythagorean identity:

sin2(t)+cos2(t)=1    1cos2(t)=sin2(t).\sin^2(t) + \cos^2(t) = 1 \implies 1 - \cos^2(t) = \sin^2(t).

Substitute this into the denominator:

1cos2(t)cos(t)=sin2(t)cos(t).\frac{1 - \cos^2(t)}{\cos(t)} = \frac{\sin^2(t)}{\cos(t)}.

So the expression becomes:

sin(t)sin2(t)cos(t).\frac{\sin(t)}{\frac{\sin^2(t)}{\cos(t)}}.


Step 4: Simplify the complex fraction

To simplify sin(t)sin2(t)cos(t)\frac{\sin(t)}{\frac{\sin^2(t)}{\cos(t)}}, multiply by the reciprocal of the denominator:

sin(t)sin2(t)cos(t)=sin(t)cos(t)sin2(t).\frac{\sin(t)}{\frac{\sin^2(t)}{\cos(t)}} = \sin(t) \cdot \frac{\cos(t)}{\sin^2(t)}.

Simplify the terms:

sin(t)cos(t)sin2(t)=sin(t)cos(t)sin2(t).\sin(t) \cdot \frac{\cos(t)}{\sin^2(t)} = \frac{\sin(t) \cos(t)}{\sin^2(t)}.

Cancel one factor of sin(t)\sin(t) from the numerator and denominator:

sin(t)cos(t)sin2(t)=cos(t)sin(t).\frac{\sin(t) \cos(t)}{\sin^2(t)} = \frac{\cos(t)}{\sin(t)}.


Step 5: Simplify to a single trigonometric function

The expression cos(t)sin(t)\frac{\cos(t)}{\sin(t)} is the cotangent function:

cos(t)sin(t)=cot(t).\frac{\cos(t)}{\sin(t)} = \cot(t).


Final Answer:

The simplified expression is:

cot(t).\cot(t).


Do you want further details or clarification on any step?

Here are some related questions for further practice:

  1. Simplify sec(t)sec(t)+tan(t)\frac{\sec(t)}{\sec(t) + \tan(t)} into a single trigonometric function.
  2. Prove the identity: sin2(t)1cos(t)=1+cos(t)\frac{\sin^2(t)}{1 - \cos(t)} = 1 + \cos(t).
  3. Simplify sin(t)csc(t)1\frac{\sin(t)}{\csc(t) - 1}.
  4. Verify: sec(t)cos(t)sec(t)=sin2(t)\frac{\sec(t) - \cos(t)}{\sec(t)} = \sin^2(t).
  5. Simplify 1cos2(t)sin(t)\frac{1 - \cos^2(t)}{\sin(t)}.

Tip:

When simplifying trigonometric expressions, always check for Pythagorean identities like 1cos2(t)=sin2(t)1 - \cos^2(t) = \sin^2(t) and reciprocal definitions to simplify fractions.

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Math Problem Analysis

Mathematical Concepts

Trigonometric Identities
Simplifying Fractions

Formulas

sec(t) = 1 / cos(t)
1 - cos^2(t) = sin^2(t)
cot(t) = cos(t) / sin(t)

Theorems

Pythagorean Identities
Reciprocal Identities

Suitable Grade Level

Grades 11-12