Solution to this trigonometric equation

In summary, the conversation is about finding the value of x in the equation tanx = ((1+tan1)(1+tan2)-2)/((1-tan1)(1-tan2)-2). The attempt at solving the problem involved multiplying through parentheses and using a trigonometric identity. The simplified form of the equation is (1 + (tan1 + tan2)/(tan1tan2-1))/(1 - (tan1 + tan2)/(tan1tan2-1)). With the help of the tan(a+b) identity, the final value of x is found to be 42 degrees.
  • #1
diredragon
323
15

Homework Statement


##tanx=\frac{(1+tan1)(1+tan2)-2}{(1-tan1)(1-tan2)-2}## find x

Homework Equations


3. The Attempt at a Solution [/B]
I tried multiplying through the paranthesis and arrived at ##tanx=\frac{(tan1tan2-1)+(tan2+tan1)}{(tan1tan2-1)-(tan2+tan1)}## and i don't know if this is any simpler than what was originally set. Is there a trigonometric identity at play here?
 
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  • #2
diredragon said:

Homework Statement


##tanx=\frac{(1+tan1)(1+tan2)-2}{(1-tan1)(1-tan2)-2}## find x

Homework Equations


3. The Attempt at a Solution [/B]
I tried multiplying through the parentheses and arrived at ##tanx=\frac{(tan1tan2-1)+(tan2+tan1)}{(tan1tan2-1)-(tan2+tan1)}## and i don't know if this is any simpler than what was originally set. Is there a trigonometric identity at play here?
Is that really tan(1) and tan(2), as in 1 and 2 radians?
 
  • #3
Whatever it is, divide the numerator & denominator by ##\ tan1\,tan2 -1 \ ##.
 
  • #4
SammyS said:
Whatever it is, divide the numerator & denominator by ##\ tan1\,tan2 -1 \ ##.
It's in degrees. So i divided both num and den by ##tan1tan2 - 1## and i get
##tanx=\frac{(tan1)^2(tan2)^2-2tan1tan2+1+(tan2)^2tan1-tan2+(tan1)^2tan2-tan1}{(tan1)^(tan2)^2-2tan1tan2+1-(tan2)^2tan1+tan2-(tan1)^2-tan1}##
What should i do now?
 
  • #5
From post #1 and using SammyS's suggestion you should get it into the form: (1 + A)/(1 - A)

Can you try it again.
 
  • #6
Oh, well then it is
##tanx=\frac{1+\frac{tan1+tan2}{tan1tan2-1}}{1-\frac{tan1+tan2}{tan1tan2-1}}##
Is there a way to simplify this?
 
  • #7
Ask google to search on tan(a+b) (or some trig expression like that) and see whether you can substitute something for that expression you have for the term I designated by A.
 
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  • #8
NascentOxygen said:
Ask google to search on tan(a+b) (or some trig expression like that) and see whether you can substitute something for that expression you have for the term I designated by A.
##tanx=\frac{1-tan3}{1+tan3}## but that's as far as the simolification goes right? Now the use of calculator is required. It says that the answer is ##x=42## in degrees.
 
  • #9
Yeah i solved it. I used ##tan45-tan3## and the identity to arrive at ##tanx=tan42##
 
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What is a trigonometric equation?

A trigonometric equation is an equation that involves one or more trigonometric functions, such as sine, cosine, or tangent, and the values of the angles involved.

How do I solve a trigonometric equation?

To solve a trigonometric equation, you must use algebraic techniques to isolate the trigonometric function and then use inverse trigonometric functions to find the angle(s) that satisfy the equation.

What are some common strategies for solving trigonometric equations?

Some common strategies for solving trigonometric equations include factoring, using trigonometric identities, applying the unit circle, and using the quadratic formula.

Are there any special cases to consider when solving trigonometric equations?

Yes, when solving trigonometric equations, it is important to consider special cases such as the period of the function, the restrictions on the domain, and the multiple solutions that may exist.

Can trigonometric equations be solved using a calculator?

Yes, many calculators have built-in functions for solving trigonometric equations. However, it is important to understand the steps involved in solving the equation by hand in order to verify the accuracy of the calculator's solution.

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