+23247 To find sin(2A):
Use formula: sin(2A) = 2sin(A)cos(A).
Draw the diagram in the third quadrant.
Since the tan(A) = 1/3, the '1' represents the y-value and the '3' represents the x-value; but, since the angle ends in the third quadrant, both the x-value and the y-value are negative.
Using the Pytagorean theorem, the hypotenuse has value √10.
Thus, sin(A) = -1/√10 and cos(A) has value -3/√10.
sin(2A) = 2(-1/√10)(-3/√10) = 6/10.
+23247 To find sin(2A):
Use formula: sin(2A) = 2sin(A)cos(A).
Draw the diagram in the third quadrant.
Since the tan(A) = 1/3, the '1' represents the y-value and the '3' represents the x-value; but, since the angle ends in the third quadrant, both the x-value and the y-value are negative.
Using the Pytagorean theorem, the hypotenuse has value √10.
Thus, sin(A) = -1/√10 and cos(A) has value -3/√10.
sin(2A) = 2(-1/√10)(-3/√10) = 6/10.
