Math Problem Statement

Use double angle to find the expression of sin^5(2x)cos(2x)

Solution

To find the expression for sin5(2x)cos(2x)\sin^5(2x)\cos(2x) using double angle identities, we can follow these steps:

Step 1: Express sin5(2x)\sin^5(2x) in terms of sin(2x)\sin(2x)

sin5(2x)=(sin(2x))5\sin^5(2x) = (\sin(2x))^5

Step 2: Use the identity for sin(2x)\sin(2x)

sin(2x)=2sin(x)cos(x)\sin(2x) = 2\sin(x)\cos(x) So, sin5(2x)\sin^5(2x) can be written as: sin5(2x)=(2sin(x)cos(x))5\sin^5(2x) = (2\sin(x)\cos(x))^5

However, we are interested in using double-angle identities to simplify the product sin5(2x)cos(2x)\sin^5(2x)\cos(2x).

Step 3: Substitute sin(4x)\sin(4x) for sin(2x)cos(2x)\sin(2x)\cos(2x)

The double angle identity for sine and cosine is: sin(4x)=2sin(2x)cos(2x)\sin(4x) = 2\sin(2x)\cos(2x) Therefore, sin(2x)cos(2x)=12sin(4x)\sin(2x)\cos(2x) = \frac{1}{2}\sin(4x)

Step 4: Substitute into the original expression

Now substitute into the expression sin5(2x)cos(2x)\sin^5(2x)\cos(2x): sin5(2x)cos(2x)=sin4(2x)sin(2x)cos(2x)\sin^5(2x)\cos(2x) = \sin^4(2x) \cdot \sin(2x) \cdot \cos(2x)

Using the identity sin(2x)cos(2x)=12sin(4x)\sin(2x)\cos(2x) = \frac{1}{2}\sin(4x), we get: sin5(2x)cos(2x)=sin4(2x)12sin(4x)\sin^5(2x)\cos(2x) = \sin^4(2x) \cdot \frac{1}{2}\sin(4x)

So the expression becomes: sin5(2x)cos(2x)=12sin4(2x)sin(4x)\sin^5(2x)\cos(2x) = \frac{1}{2}\sin^4(2x)\sin(4x)

Final Answer:

sin5(2x)cos(2x)=12sin4(2x)sin(4x)\sin^5(2x)\cos(2x) = \frac{1}{2}\sin^4(2x)\sin(4x)

Would you like to go into further detail, or do you have any questions?


Here are some related questions you might find interesting:

  1. How would you simplify cos5(2x)sin(2x)\cos^5(2x)\sin(2x) using double angle identities?
  2. What is the expression for cos4(2x)sin(2x)cos(2x)\cos^4(2x)\sin(2x)\cos(2x)?
  3. How would you find the expression for sin6(2x)\sin^6(2x) using trigonometric identities?
  4. What is the double angle identity for sin(2x)\sin(2x) and how is it derived?
  5. How would you express sin3(2x)cos(4x)\sin^3(2x)\cos(4x) using trigonometric identities?
  6. What are the identities for sin2(x)\sin^2(x) and cos2(x)\cos^2(x) in terms of double angles?
  7. How would you express sin3(x)cos(x)\sin^3(x)\cos(x) using sum-to-product identities?
  8. What is the relationship between sin(4x)\sin(4x) and sin(2x)cos(2x)\sin(2x)\cos(2x)?

Tip: When dealing with trigonometric identities, always try to simplify the expressions step by step by using fundamental identities like double-angle or sum-to-product formulas.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Double Angle Identities

Formulas

Double angle identity for sine and cosine

Theorems

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Suitable Grade Level

High School