Question

prove this ..............

Answer 1

sec^2 A - tan^2=1
1+tan^2-tan^2A=1
1=1

Answer 2

x^2+y^2=r^2
division by x^2
(x/x)^2+(y/x)^2=(r/x)^2 y/x=tanA r/x=secA


1+tan^2A=sec^2A
sec^2A-tan^2A=1