# cos (180 - theta) = 8

• February 7th 2010, 06:06 AM
protractor
cos (180 - theta) = 8
hello,

I'm working on a question involving resolving forces in equilibrium.

I don't know if I've been doing it right, but I've ended up with:

cos (180 - theta) = 8

Theta is an angle that I need to find.

Is there any way of manipulating the above in order to find theta?
• February 7th 2010, 06:16 AM
dedust
Quote:

Originally Posted by protractor
hello,

I'm working on a question involving resolving forces in equilibrium.

I don't know if I've been doing it right, but I've ended up with:

cos (180 - theta) = 8

Theta is an angle that I need to find.

Is there any way of manipulating the above in order to find theta?

maximum of $\cos(180 - \theta)$ is 1, so there is no way $\cos(180 - \theta) = 8$
• February 7th 2010, 01:34 PM
protractor
thanks
Quote:

Originally Posted by dedust
maximum of $\cos(180 - \theta)$ is 1, so there is no way $\cos(180 - \theta) = 8$

Thanks for that useful information Dedust, I can definitely abandon that route then! I've actually realised now that I can actually tackle the question using good old Pythagoras, so simple, yet so useful!