Given sin A = 4/5 and cos A < 0, find tan A

tan A = -

Step-by-step explanation:

Using the identity sin² A + cos² A = 1, then

( )² + cos² A = 1

+ cos² A = 1 ( subtract from both sides )

cos² A = ( take the square root of both sides )

cos A = ± and given cosA < 0, then

cos A = -

Using the identity

tan A = , then

tan A = = × - = -

step-by-step explanation:

answer4 to the second power is 16

and 4 to the third power is 64,