SOLUTION: Find the point on the terminal side of theta = - (3pi)/4 that has an x coordinate of -1

Algebra ->  Trigonometry-basics -> SOLUTION: Find the point on the terminal side of theta = - (3pi)/4 that has an x coordinate of -1      Log On


   



Question 1168720: Find the point on the terminal side of theta = - (3pi)/4 that has an x coordinate of -1
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
use your calculator to find that tan(-3/4 * pi) = 1
x-coordinate of terminal point is -1.
since tangent is equal to opposite / adjacent, then tangent = y/x = 1
when x = -1, you get y/-1 = 1
solve for y to get:
y = 1*-1 = -1
the coordinate point is (-1,-1).
here's my picture of what it looks like.

the angle, being negative, rotates about the graph in a clockwise direction.
you can see from the graph that the reference angle is pi/4.
that's because the angle from the right side x-axis to the left side x-axis is pi and (3/4 * pi) + (1/4) * pi = (4/4 * pi) = pi.