Question

if tanx=3/4 and x lies in 3rd quadrant ,find sinx

Answer 1

According to the problem given ,

tanx lies in 3rd quadrant .

tanx = 3/4 [ given ]

In ∆OAB ,

<A = 90°

By Phythogarian theorem ,

OB² = OA² + AB²

= ( -4 )² + (-3 )²

= 16 + 9

= 25

= 5²

OB = 5

Now ,

sinx = AB/OB

= -3/5

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