1)If sin(t) = -5/13 and 270 degrees is less than or
equal to t and is less than or equal to 360 degrees,
2)If 0 degrees is less than t and less than 90 degrees
and cos(t) = 4/5, then cos(2t)=?
3)A right triangle is shown, sec(t) =? . |
1 = hypotenuse . |
x = y side of triangle . | x
t = inside angle < t___________|
1) Using that cos^2+sin^2=1 we get: cos(t)^2=1-25/169=144/169=(12/13)^2 so cos(t)=12/13 or cos(t)=-12/13. Because t is in the fourth quarter, cos(t) ...
This shows how to work with trigonometric functions and angles.