Solve Math Problem: Simplify \sin\theta\sec\theta+\cos\theta\csc\theta

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In summary, the conversation discusses simplifying the expression \sin\theta\sec\theta+\cos\theta\csc\theta using reciprocal, quotient, and Pythagorean identities. After several attempts, the simplified form is determined to be \tan\theta+\cot\theta or \frac{1}{\cos\theta\sin\theta}. Another suggestion is made to use 2cosec(2\theta) if the student is familiar with double-angles.
  • #1
PanTh3R
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Homework Statement


simplify:
[tex] \sin\theta\sec\theta+\cos\theta\csc\theta[/tex]


Homework Equations


Reciprocal identities, Quotient identities, Pythagorean identities


The Attempt at a Solution



[tex] \sin\theta\sec\theta+\frac{1}{\sec\theta}\frac{1}{\sin\theta}[/tex]

[tex] \sin\theta\sec\theta+\frac{1}{\sin\theta\sec\theta}[/tex]

and this is where i get stuck...can i get help from anyone?
 
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  • #2
Hi PanTh3R! :smile:

(have a theta: θ :wink:)

You need to be systematic …

keep all the sin and cos, get rid of the sec and csc. :wink:

Try again. :smile:
 
  • #3


so i get...

[tex]\sin\theta\frac{1}{\cos\theta}+cos\theta\frac{1}{\sin\theta}[/tex]

then i put each in one fraction right?

[tex]\frac{\sin\theta}{\cos\theta}+\frac{\cos\theta}{\sin\theta}[/tex]

to

[tex]\tan\theta+cot\theta[/tex]

is that the simplest it can get?
 
  • #4
Hi PanTh3R! :wink:

This is elementary algebra …

put both fractions over the same denominator (the LCM). :smile:
 
  • #5


im sorry I am really bad with these i just started doing them um so i do

[tex]\frac{\sin^2\theta+\cos\theta}{\cos\theta\sin\theta}[/tex]

i still don't get it won't that make it more complicated? :confused:
 
  • #6
Bottom right, top wrong. :wink:
 
  • #7


would it be...

[tex]\frac{\sin^2\theta+\cos^2\theta}{\cos\theta\sin\theta}[/tex]

then

[tex]\frac{1-\cos^2+\cos^2\theta}{\cos\theta\sin\theta}[/tex]

into

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

i feel so frustrated :confused: sry
 
  • #8


Looks like that's the simplest you can get it.
 
  • #9


Bohrok said:
Looks like that's the simplest you can get it.

[tex]2cosec(2\theta)[/tex] would seems better.
 
  • #10


It depends if the OP has been exposed to double-angles yet. Trigonometric simplifications of this form are commonly taught before the student ever learns that [itex]2sin\theta cos\theta=sin(2\theta)[/itex]
 

1. What is the purpose of simplifying this math problem?

The purpose of simplifying this math problem is to make the expression easier to work with and understand. Simplifying can also help identify patterns and relationships between different terms in the expression.

2. How do I simplify this expression?

To simplify this expression, you can use the trigonometric identities of $\sin\theta\cos\theta=\frac{1}{2}\sin2\theta$ and $\sec\theta=\frac{1}{\cos\theta}$ to rewrite the expression as $\frac{1}{2}\sin2\theta+\frac{1}{\sin\theta}$. Then, you can use the common denominator of $\sin\theta$ to simplify further into $\frac{\sin2\theta+2}{2\sin\theta}$.

3. Can this expression be simplified further?

No, this expression cannot be simplified any further. It is already in its simplest form.

4. What are the possible values for $\theta$ in this expression?

The possible values for $\theta$ in this expression are any real numbers except for values that make the expression undefined, such as $\theta=\frac{\pi}{2}$ for $\csc\theta$ and $\theta=0$ for $\sec\theta$.

5. How can simplifying this expression be useful in real-world applications?

Simplifying this expression can be useful in real-world applications where trigonometric functions are used, such as in engineering, physics, and surveying. It can also help in solving equations and problems involving trigonometric functions.

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