Trigonometry - compound angels

In summary, the conversation discusses how to evaluate tan(37+23) without using a calculator or tables. Suggestions are given to use identities and the tangent of a sum formula to solve the problem. The final answer is given as √3.
  • #1
Michael_Light
113
0

Homework Statement



Evaluate http://img828.imageshack.us/img828/3383/msp588119g042f0f3ba0368.gif without using calculator or tables.

Homework Equations





The Attempt at a Solution



I have no ideas how tan37 and tan23 can be found... can anyone give me some hints? The answer given is √3. Thank you...
 
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  • #2
I don't think you're meant to evaluate tan 37 and tan 23 directly, but do you know any identities which may be used? Like any sum of sin or cos rules? Hint: break tan down into it's sin and cos parts.

(37+23 = 60, and I'd wager you know the sin cos and tan of 60)
 
  • #3
Actually, I don't think you need to express tangent in terms of sine and cosine. Just use the tangent of a sum identity.

Given
[tex]\tan (a + b) = \frac{\tan a + \tan b}{1 - \tan a \tan b}[/tex]

solve for "tan a + tan b".
 
  • #4
Compound "angels" huh?

You know, of course, that there's a difference between an angel and an angle?:wink:
 

1. What is a compound angle in trigonometry?

A compound angle in trigonometry is an angle that is formed by combining two or more simpler angles. It is represented by the sum or difference of the simpler angles.

2. How do you find the values of compound angles?

The values of compound angles can be found using trigonometric identities and formulas. For example, the sum or difference of two angles can be found using the sum and difference identities, and the double angle formula can be used to find the value of an angle that is twice another angle.

3. What are the applications of compound angles in real life?

Compound angles have many applications in fields such as engineering, physics, and navigation. They can be used to calculate the trajectory of a projectile, determine the direction and speed of wind, and even design structures such as bridges and buildings.

4. Can compound angles be negative?

Yes, compound angles can be negative. When an angle is negative, it means that it is measured in the opposite direction of positive angles. This is commonly seen in the trigonometric functions cosine and secant, where negative angles are located in the third and fourth quadrants.

5. How can I simplify expressions involving compound angles?

To simplify expressions involving compound angles, you can use trigonometric identities and formulas. For example, the product formula can be used to simplify expressions with two angles multiplied together, and the quotient formula can be used to simplify expressions with two angles divided by each other.

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