if tan=15/8 and cos negative then what is the value of [sin(-a)-cosa]/[tan(-a)+sec(-a)]

Answer 1

Then tan is +, and the cos is -, so you must be in quadrant III

tan a = 15/8 = y/x
so y = -15 , x = -8, and r = 17

[sin(-a)-cosa]/[tan(-a)+sec(-a)]
= (-sina - cosa)/(-tana + seca)
= (15/17 + 8/17)/(-15/8 - 17/8)
= (23/17)(-8/32)
= -23/68

Answer 2

This isnt the correct way u wont get the full marks for this sum if follow the above way... It should be soved by using the trigonometric formula

Answer 3

Thank you sir for solving this sum....... if we follow the trigonometric way then it will be very easy