Respostas

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2014-06-02T16:03:49-03:00
Cos²x+sen²x=1
sen²=1-cos²
sen²=1-(4/5)²
sen²=1-16/25
sen²=9/25
sen=-3/5

A) cotg x = cos x /sen x
4/5/-3/5 =
4/5*-5/3 =
-20/15

B) sec x = 1/cos x
1/4/5 =
1*5/4 =
5/4

C) cossec x = 1/sen
1/-3/5 =
1*-5/3 =
-5/3
3 5 3