If A is a positive position angle of the point, (4, -2), answer each of the following.Rationalize all the denominators.
a) sin A=
b) cos A=
c)tan A=
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I got -(square root of 20) for sine, (square root of 20) over 5 for cosine, and -1/2 for tangent. I got tangent right but what did I do wrong for the other two? Am I rationalizing the denominators wrong?
you have
x = 4
y = -2
r = √20
sinA = y/r = -2/√20 = -2/(2√5) = -1/√5 = -√5/5
cosA = x/r = 4/√20 = 4/(2√5) = 2/√5 = 2√5/5
tanA = y/x = -2/4