Find sin 2x, cos 2x, and tan 2x from the given information:
sin x = 8/17, x in Quadrant I
sin 2x = ____
cos 2x = ____
tan 2x = ____
Draw the angle, and you have
y = 8
r = 17
x = 15
so
cosx = x/r = 15/17
sin2x = 2sinx cosx = 2(8/17)(15/17) = 240/289
cos2x = cos^2x - sin^2x = 161/289
tan2x = sin2x/cos2x = 240/161