Question

If Sin A + Cos A = 21 then prove that Sin A - cos a = 2 + - 1

Answer 1

Sin A+ Cos A=21

Sin A= 21- Cos A

To prove

Sin A- Cos A= 2 + (-) 1


21- Cos A- Cos A= 2+(-)1

21-2cos A = 1

21-1=2cosA
20=2cosA
cosA=20/2=10
cosA=10{Answer}