PRECALC
posted by Billy NEED HELP .
sin(arctan(4/3)
okay so i made arctan(4/3) = x
so im solving for sin(x)
and x= arctan(4/3)
so then tanx = 4/3
and now im stuck i don't know what to do after that

Draw the right triangle (3,4,5)
3^2+4^2 = 9+16 = 25 = 5^2
angle A = atan(4/3)
sin A = 4/5
now look for quadrant
tan = 4/3 in quadrant 2 and in quadrant 4
in quadrant 2 sin A = 4/5
in quadrant 4 sin A = 4/5 
just draw the triangle
tan = y/x
sin = y/h
h = 5 (345 triangle!)
principal value of arctan(4/3) is in QIV.
sin = 4/5
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