
Hello. I am having difficulty with this problem:
Find the point on the terminal side of θ = 3pi/4 that has an x coordinate of 1
I was hoping that someone here would be able to help me out? I am actually trying to figure out what I am doing so if you could explain how you found the answer, I would really appreciate it. Thank you so much guys.

Re: terminal side

Re: terminal side
oops, sorry.
θ=3pi/4
Thanks

Re: terminal side
From the given information, we know:
The coordinate is then:

Re: terminal side

Re: terminal side
No, what is ?

Re: terminal side

Re: terminal side
No, the sine of an angle will not return an angle. is a special angle for which you should know the trig. functions at that angle.
So, the coordinate of the point is:
Recall we found hence:
And so, the point in question is (1,1). Try drawing a diagram, and you will easily see that the coordinate has to be equal to the coordinate, as the given angle lies along the line .

Re: terminal side
I see what you mean now. Thanks for telling me to draw a diagram. That made it easier for me to understand. So pi/4 is one of those I just need to memorize then right?
Thanks so much bro.

Re: terminal side
Well, it's a lot easier to memorize if you understand it. Imagine a right triangle having one angle of and one leg of length 1. Since , so that the other angle is also which means that the other leg also has length 1. By the Pythagorean theorem, the length of the hypotenuse is given by so that . That gives .

Re: terminal side
Could someone send me a link to teach me how to do this? I'm afraid I don't even understand it...