Question

if r sin a=2/ root 3 and r cos a=2/3, then show that a =60 degree, r=4/3​

Answer 1

Answer:

r sinA = 2/$\sqrt3$

r cosA = 2/3

Square on both, then add

= > (rsinA)^2 + (rcosA)^2 = 4/3 + 4/9

= > r^2[ sin^2A + cos^2 A ] = ( 12 + 4 )/9

= > r^2 ( 1 ) = 16/9

= > r^2 = 16/9

= > r = 4/3, Proved

r cosA = 2/3

= > (4/3) cosA = 2/3

= > 4 cosA = 2

= > cosA = 1/2

= > cosA = cos60*

= > A = 60* , Proved