CosA 513 A is in Q IV Find tanA 125 125 512 512 Simplify si

CosA = 5/13, A is in Q IV. Find tanA -12/5 12/5 5/12 -5/12 Simplify sin^4A - cos^4A + cos^2A sin^2 A^sin cos^2A - sin^2 A cos^2A - sin^4A 1

Solution

11) cosA = 5/13 ; A is in QIV

tanA = - 12/13

12) sin^4A - cos^4A +cos^2A

= (sin^2A+ cos^2A)(sin^2A -cos^2A) +cos^2A

= 1(sin^2A - cos^2A) +cos^2A

= sin^2A