A is an acute angle and cos A=5/13. Without using multiplication or calculator,find the value of each of the following trigonometry function a) cos (180°-A) b) sin (180°-A) c) tan (180°+A) ?

1 Answer
Mar 17, 2018

We know,that,

cos(180-A)=-cos A=-5/13

sin(180-A)= sin A=sqrt(1-cos^2 A)=12/13

tan(180+A)= sin(180+A)/cos(180+A)=(-sin A)/(-cos A)=tan A=12/5