# Simplifying Trigonometric Expression

• February 16th 2013, 05:45 PM
vaironxxrd
Simplifying Trigonometric Expression
 Hello Everyone, I'm trying to figure out how to simplify the following. I'm trying to solve it but I'm not getting any of my answer choices. If someone could give me one example for only one I believe I could figure out the other ones. http://www.webassign.net/cgi-perl/sy...(sec^2(x) - 1) http://www.webassign.net/cgi-perl/sy...(x) - tan^4(x)

http://www.webassign.net/cgi-perl/sy...)-x))%2Fcos(x)

http://www.webassign.net/cgi-perl/sy...)%2F(sin^2(x))

http://www.webassign.net/cgi-perl/sy...=cot(x) sec(x)

My attempt:

http://www.webassign.net/cgi-perl/sy...(sec^2(x) - 1) = $Cos^2(x)(tan^2(x))$ = $\frac{adj^2}{hyp^2} \cdot \frac{opp^2}{adj^2} = sin^2(x)$

http://www.webassign.net/cgi-perl/sy...)-x))%2Fcos(x) = $\frac{sin^2(x)}{cos(x)}$ STUCK

http://www.webassign.net/cgi-perl/sy...)%2F(sin^2(x)) = $\frac{tan^2(x)}{sin^2(x)} = csc^2(x)$ <- Is there any other way to rewrite this? Is not in one of my choices

http://www.webassign.net/cgi-perl/sy...ot(x)%20sec(x) = $csc(x)$
• February 16th 2013, 06:38 PM
zhandele
Re: Simplifying Trigonometric Expression
On the first one, I get the same answer you did.

On the second, you could write tanx sinx.

On the third, I think you mean sec^2(x) not cosecant.

On the fourth, again I get the same result you did.

The one about the fourth powers, for which you didn't show an attempt ... it's a difference of two squares, isn't it? And one of the factors will be another difference of squares, right? Does that help?

What are the choices available?
• February 16th 2013, 10:06 PM
earthboy
Re: Simplifying Trigonometric Expression
trig identities can be expressed and molded into different forms...You can get correct answers but it may not still match your form.Give the forms available...and then we will try to shape the trig functions that way...
• February 17th 2013, 10:42 AM
vaironxxrd
Re: Simplifying Trigonometric Expression
Quote:

Originally Posted by zhandele
On the first one, I get the same answer you did.

On the second, you could write tanx sinx.

On the third, I think you mean sec^2(x) not cosecant.

On the fourth, again I get the same result you did.

The one about the fourth powers, for which you didn't show an attempt ... it's a difference of two squares, isn't it? And one of the factors will be another difference of squares, right? Does that help?

What are the choices available?

Quote:

Originally Posted by earthboy
trig identities can be expressed and molded into different forms...You can get correct answers but it may not still match your form.Give the forms available...and then we will try to shape the trig functions that way...

I was able to figure them out by trial-and-error.

The second is as Zhandele stated.

On last one is $sin^2(x) + tan^2(x)$

Again I din't figure it out I did it by trial-and-error and plugin in values for x.

I thank you both for the help.