1. ## Trig with Pi?

I have the question
a) 3sin(2pi/3) + 2tan(5pi/4)
I have to solve it without a calculator, could you explain step by step how you did it? Thanks.

2. ## Re: Trig with Pi?

You need to understand the unit circle and trig identities to solve this.

Here's a start

$\sin \frac{2\pi}{3}=\sin \frac{\pi}{3}$

and

$\tan \frac{5\pi}{4}=\tan \frac{\pi}{4}$

3. ## Re: Trig with Pi?

First of all, thank you for taking the time to help me and all, much appreciated.
To my understanding, sin (2pi/3) is pretty much a third of the unit circle located in the 2nd quadrant, then we find the RAA which makes it sin(pi/3), am I correct? Also, I have some problems visualizing the unit circle. Is there any easier way to visualize if you have a question like sin (11pi/6)?
Anyways, continuing with the question
=3sin(pi/3) + 2tan (pi/4)
=3(1/2) + 2(1)
=5/2
Is this correct?

4. ## Re: Trig with Pi?

For better visualisation, you can convert radians to degrees by the following formula:

$\theta_{R}=\frac{360^{\circ}}{2\pi}\theta_{D}$