Last edited by SarahGr; May 14th 2009 at 08:29 PM.
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Originally Posted by SarahGr I have one more question for you guys here's what I was given
Suppose sinα = 4/5 and tanβ= -3/4 where π/2 < α < β < π (pi) the above inequality tells you the quadrant where α and β both reside.
Sin(α + β)
Cos(α + β)
Tan(α + β)
What i have been doing is figuring out the other trig functions
They gave me sinα=4/5 and tanβ=-3/4 the signs of your trig values below were all incorrect ... α and β are both quadrant II angles ... sine is positive, cosine and tangent are negative.
note the changes ...
from that i found cosα = -3/5 tanα = -3/4 and sinβ = +3/5 cosβ = -4/5
I tried problem a ... redo it
sin(α+β)=4/5 * 4/5 + 3/5 * -3/5
which gives me 7/25 but I'm not sure I am doing this right... what is the whole (π/2 < α < β < π) thing about am I supposed to be finding points on the unit circle or something? understand now? =/ .
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