Question Number 5479 by keagan j last updated on 15/May/16
$${cos}\mathrm{180}.{tan}\left(−{x}\right) \\ $$
Answered by Rasheed Soomro last updated on 15/May/16
![cos 180=−1,tan(−x)=−tan(x) [tan is odd function] ∴ cos180.tan(−x)=(−1)(−tan x) =tan x](Q5480.png)
$${cos}\:\mathrm{180}=−\mathrm{1},{tan}\left(−{x}\right)=−{tan}\left({x}\right)\:\left[{tan}\:\:{is}\:{odd}\:{function}\right] \\ $$$$\therefore\:{cos}\mathrm{180}.{tan}\left(−{x}\right)=\left(−\mathrm{1}\right)\left(−{tan}\:{x}\right) \\ $$$$={tan}\:{x} \\ $$