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Trigo.
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You are currently reading a thread in /sci/ - Science & Math

Can someone explain to me or help me understand how,
sin2(b) if tan(b) = -3/4 and cos(b) > 0 can equal to -24/25? please
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Well, since you didn't give us angles we can't really help you lol..because;

Sin is a/c and cos is b/c, and finally tan is a/b but without the 3 angles of the triangle(a,b,c) it's hard to help buddy
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>>7794613
OP is a faggot as usual: >>7794594
>>
>>7794613
This belongs in /sqt/ but I'll bite. Since the tangent is negative and cos(b)>0, sin(b)<0. let cos b = c. sin(b) = -sqrt(1-c^2), the negative value.
Solve for c in this: tan(b) = -sqrt(1-c^2)/c = -3/4
then evaluate sin (2b) using the double angle identity.