Question Number 100815 by john santu last updated on 28/Jun/20

Answered by mr W last updated on 28/Jun/20

see Q47657 δ=(2+3+(√7))(−2+3+(√7))(2−3+(√7))(2+3−(√7)) =108 side length of equilateral triangle: l=(√((2^2 +3^2 +((√7))^2 +(√(3×108)))/2))=(√((20+18)/2))=(√(19)) cos α=((19+4−7)/(2×(√(19))×2))=((4(√(19)))/(19)) ⇒tan α=((√3)/4) cos β=((19+9−7)/(2×(√(19))×3))=((7(√(19)))/(38)) ⇒tan β=((3(√3))/7) tan (α+β)=((tan α+tan β)/(1−tan α tan β)) =((((√3)/4)+((3(√3))/7))/(1−((√3)/4)×((3(√3))/7)))=(√3) ⇒Answer A

Commented bybramlex last updated on 29/Jun/20

what is δ sir?

Commented bymr W last updated on 29/Jun/20

see formula in Q47657

Commented bymr W last updated on 29/Jun/20