Math Problem Statement

can you show all steps in verifying the euqation 1/cot x + tan x = sinx/secx

Solution

Sure! Let's break down and verify the equation:

1cotx+tanx=sinxsecx\frac{1}{\cot x} + \tan x = \frac{\sin x}{\sec x}

Step 1: Express cotx\cot x and tanx\tan x in terms of sine and cosine

We know the following trigonometric identities: cotx=cosxsinxandtanx=sinxcosx\cot x = \frac{\cos x}{\sin x} \quad \text{and} \quad \tan x = \frac{\sin x}{\cos x}

So, we can rewrite the left-hand side of the equation:

1cotx=1cosxsinx=sinxcosx\frac{1}{\cot x} = \frac{1}{\frac{\cos x}{\sin x}} = \frac{\sin x}{\cos x}

Thus, the left-hand side becomes:

sinxcosx+sinxcosx=2sinxcosx\frac{\sin x}{\cos x} + \frac{\sin x}{\cos x} = 2 \cdot \frac{\sin x}{\cos x}

Step 2: Simplify the right-hand side

Now let's simplify the right-hand side of the equation. Recall the identity secx=1cosx\sec x = \frac{1}{\cos x}, so:

sinxsecx=sinx1cosx=sinxcosx\frac{\sin x}{\sec x} = \frac{\sin x}{\frac{1}{\cos x}} = \sin x \cdot \cos x

Step 3: Compare both sides

We now have:

  • Left-hand side: 2sinxcosx2 \cdot \frac{\sin x}{\cos x}
  • Right-hand side: sinxcosx\sin x \cdot \cos x

The equation becomes: 2sinxcosx=sinxcosx2 \cdot \frac{\sin x}{\cos x} = \sin x \cdot \cos x

Step 4: Check if both sides are equal

Let’s try to simplify and see if both sides are equal:

  • Left-hand side: 2sinxcosx=2sinxcosx2 \cdot \frac{\sin x}{\cos x} = \frac{2 \sin x}{\cos x}
  • Right-hand side: sinxcosx\sin x \cdot \cos x

Clearly, the two sides are not equivalent for all values of xx. The equation doesn't hold true for all values of xx.

Conclusion

The given equation:

1cotx+tanx=sinxsecx\frac{1}{\cot x} + \tan x = \frac{\sin x}{\sec x}

is not valid for all values of xx.


If you would like more details or have any questions, feel free to ask!

Here are some related questions:

  1. Can you explain why 1cotx\frac{1}{\cot x} is equivalent to tanx\tan x?
  2. How do you prove trigonometric identities using a different method, like common denominators?
  3. What other common trigonometric identities should be memorized for simplification?
  4. How would the equation change if we had secx+tanx\sec x + \tan x on the left-hand side instead of 1cotx+tanx\frac{1}{\cot x} + \tan x?
  5. What are the specific values of xx for which the given equation could hold true?

Tip: When verifying or proving trigonometric identities, always try to express all terms in terms of sine and cosine, as this often simplifies the problem.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Trigonometric Identities

Formulas

cot x = cos x / sin x
tan x = sin x / cos x
sec x = 1 / cos x

Theorems

Verification of trigonometric identities

Suitable Grade Level

Grades 9-11