Question

(UFSC) Se cossec=5/4, x que pertence ao primeiro quadrante, calcule 2 cotg x + sen x​

Answer 1

cossec x = 1 / sen x

1/ sen x = 5/4

5 sen x = 4

sen x = 4/5

sen ² x+ cos ²x = 1

(4/5) ² + cos ²x = 1

cos ²x = 1 - 16/25

cos ²x = 9/25

cos x= √(9/25)

cos x= 3/5

...

2 . cos x/ sen x + sen x =

2 . (3/5)/(4/5) + (4/5) =

2. (3/4) + (4/5) =

3/2 + 4/5 =

15/10 + 8/10 =

23/10 =

2,3