Can you help me solve this trig identity question?

In summary, the conversation involves proving an equation involving trigonometric functions. The first step involves converting the left side to sines and cosines, and the second step involves using the relationship between cotangent and tangent to simplify the expression.
  • #1
x.xmedzx.x
7
0
hey guyz...ok iv been trying to figure this question out for so long...and i jus can't.i get up to a certain point and then i jus get confused.so if anyone can help me that would be great!

Prov that:
Cos^2x + Cotx ÷ Cos^2x – Cotx = Cos^2x (tanx) + 1 ÷ Cos^2x (tanx) -1
 
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  • #2
[tex] \frac{\cos^{2}x + \cot x}{\cos^{2}x-\cot x} = \frac{\cos^{2}x(\tan x)+1}{\cos^{2} x(\tan x) -1} [/tex]

Convert the left side to sines and cosines:

[tex] \frac{\cos^{2}x + \frac{\cos x}{\sin x}}{\cos^{2}x - \frac{\cos x}{\sin x}} = \frac{\cos^{2}x\sin x + \cos x}{\sin x}\frac{\sin x}{\cos^{2}x\sin x - \cos x} = \frac{\cos^{2}x\sin x + \cos x}{\cos^{2}x\sin x - \cos x} = \frac{\cos^{2}x(\sin x + \frac{1}{\cos x})}{\cos^{2}x(\sin x - \frac{1}{\cos x})} [/tex].

Can you go from there?
 
Last edited:
  • #3
umm ok the first setp i got...but the 2nd one I am a little bit confused as to what you did...
 
  • #4
x.xmedzx.x said:
umm ok the first setp i got...but the 2nd one I am a little bit confused as to what you did...
Note that;

[tex]\cot\theta=\frac{1}{\tan\theta}=\frac{1}{\frac{\sin\theta}{\cos\theta}}=\frac{\cos\theta}{\sin\theta}[/tex]
 

FAQ: Can you help me solve this trig identity question?

What is the purpose of proving trigonometric identities?

Proving trigonometric identities is important because it allows us to manipulate and simplify trigonometric expressions, making them easier to work with in calculations and problem solving. It also helps us understand the relationships between different trigonometric functions and how they are related to each other.

What are the basic trigonometric identities?

The basic trigonometric identities include the Pythagorean identities, reciprocal identities, quotient identities, and even-odd identities. These identities are used to simplify and manipulate trigonometric expressions, and are essential in proving more complex identities.

What are some tips for proving trigonometric identities?

Some tips for proving trigonometric identities include starting with the more complex side of the equation, using known identities as a starting point, and using algebraic manipulations to rearrange the expressions. It is also helpful to keep in mind the definitions of the trigonometric functions and their relationships to each other.

What are common mistakes to avoid when proving trigonometric identities?

Common mistakes to avoid when proving trigonometric identities include making algebraic errors, forgetting to use the correct identities, and not simplifying the expressions fully. It is also important to remember to check both sides of the equation to ensure that they are equivalent.

How can proving trigonometric identities be used in real life?

Proving trigonometric identities can be useful in a variety of real-life applications, such as in engineering, physics, and navigation. It can also be used to solve problems involving angles and distances, and to find unknown values in geometric figures and shapes. Additionally, understanding trigonometric identities can be helpful in advanced mathematics courses and in further studies in science and technology fields.

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