Math Problem Statement

We are given the expression:

e x − ln ⁡ ( cos ⁡ 2 ( x ) ) + ln ⁡ ( 1 + tan ⁡ 2 ( x ) ) . e x −ln(cos 2 (x))+ln(1+tan 2 (x)). Let's simplify this step by step.

Step 1: Simplifying ln ⁡ ( cos ⁡ 2 ( x ) ) ln(cos 2 (x)) We use the logarithmic property ln ⁡ ( a b )

b ln ⁡ ( a ) ln(a b )=bln(a), where a

cos ⁡ ( x ) a=cos(x) and b

2 b=2. Thus,

ln ⁡ ( cos ⁡ 2 ( x ) )

2 ln ⁡ ( cos ⁡ ( x ) ) . ln(cos 2 (x))=2ln(cos(x)). So the expression becomes:

e x − 2 ln ⁡ ( cos ⁡ ( x ) ) + ln ⁡ ( 1 + tan ⁡ 2 ( x ) ) . e x −2ln(cos(x))+ln(1+tan 2 (x)). Step 2: Simplifying ln ⁡ ( 1 + tan ⁡ 2 ( x ) ) ln(1+tan 2 (x)) Recall the trigonometric identity 1 + tan ⁡ 2 ( x )

sec ⁡ 2 ( x ) 1+tan 2 (x)=sec 2 (x). Using this identity, we have:

ln ⁡ ( 1 + tan ⁡ 2 ( x ) )

ln ⁡ ( sec ⁡ 2 ( x ) )

2 ln ⁡ ( sec ⁡ ( x ) ) . ln(1+tan 2 (x))=ln(sec 2 (x))=2ln(sec(x)). Now the expression becomes:

e x − 2 ln ⁡ ( cos ⁡ ( x ) ) + 2 ln ⁡ ( sec ⁡ ( x ) ) . e x −2ln(cos(x))+2ln(sec(x)). Step 3: Using the identity sec ⁡ ( x )

1 cos ⁡ ( x ) sec(x)= cos(x) 1 ​

Next, we use the fact that sec ⁡ ( x )

1 cos ⁡ ( x ) sec(x)= cos(x) 1 ​ . Therefore, we can rewrite ln ⁡ ( sec ⁡ ( x ) ) ln(sec(x)) as:

ln ⁡ ( sec ⁡ ( x ) )

ln ⁡ ( 1 cos ⁡ ( x ) )

− ln ⁡ ( cos ⁡ ( x ) ) . ln(sec(x))=ln( cos(x) 1 ​ )=−ln(cos(x)). Substituting this into the expression, we get:

e x − 2 ln ⁡ ( cos ⁡ ( x ) ) + 2 ( − ln ⁡ ( cos ⁡ ( x ) ) )

e x − 2 ln ⁡ ( cos ⁡ ( x ) ) − 2 ln ⁡ ( cos ⁡ ( x ) ) . e x −2ln(cos(x))+2(−ln(cos(x)))=e x −2ln(cos(x))−2ln(cos(x)). This simplifies further to:

e x − 4 ln ⁡ ( cos ⁡ ( x ) ) . e x −4ln(cos(x)). Final Simplified Expression: Thus, the simplified expression is:

e x − 4 ln ⁡ ( cos ⁡ ( x ) ) . e x −4ln(cos(x)). what is the true topics of this solution

Solution

The true topics involved in this solution encompass:

  1. Exponential and Logarithmic Functions: The expression includes the exponential function exe^x and the logarithmic function ln(x)\ln(x). You use logarithmic properties, such as ln(ab)=bln(a)\ln(a^b) = b\ln(a), to simplify terms like ln(cos2(x))\ln(\cos^2(x)).

  2. Trigonometric Identities: The trigonometric identity 1+tan2(x)=sec2(x)1 + \tan^2(x) = \sec^2(x) is applied to simplify ln(1+tan2(x))\ln(1 + \tan^2(x)) into ln(sec2(x))\ln(\sec^2(x)).

  3. Logarithmic Manipulations: The properties of logarithms are used throughout, including the fact that ln(1a)=ln(a)\ln(\frac{1}{a}) = -\ln(a). This is crucial when simplifying terms like ln(sec(x))\ln(\sec(x)) into ln(cos(x))-\ln(\cos(x)).

  4. Trigonometric Function Relationships: The relationship between sec(x)\sec(x) and cos(x)\cos(x), i.e., sec(x)=1cos(x)\sec(x) = \frac{1}{\cos(x)}, is used to further simplify the expression.

  5. Simplification Techniques: Algebraic simplifications, combining terms like 2ln(cos(x))2\ln(\cos(x)) and 2(ln(cos(x)))2(-\ln(\cos(x))), are key to reaching the final expression.

These topics are foundational in calculus and pre-calculus, involving functions, identities, and the interplay between exponential, logarithmic, and trigonometric expressions.

Do you want details or have any questions?


Here are 5 related questions to deepen your understanding:

  1. How does the property ln(ab)=bln(a)\ln(a^b) = b\ln(a) apply to different functions?
  2. What is the significance of the identity 1+tan2(x)=sec2(x)1 + \tan^2(x) = \sec^2(x)?
  3. How does logarithmic simplification affect the domain of the functions involved?
  4. What other trigonometric identities can simplify complex expressions like this?
  5. How can this technique be used to solve logarithmic equations?

Tip: Always keep in mind domain restrictions when simplifying logarithmic and trigonometric functions, especially with ln(x)\ln(x) and cos(x)\cos(x).

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Math Problem Analysis

Mathematical Concepts

Exponential and Logarithmic Functions
Trigonometric Identities
Logarithmic Manipulations
Trigonometric Function Relationships
Simplification Techniques

Formulas

ln(a^b) = b ln(a)
1 + tan^2(x) = sec^2(x)
ln(sec(x)) = −ln(cos(x))

Theorems

Logarithmic Properties
Trigonometric Identities

Suitable Grade Level

Grades 10-12