Question

if cos A = 2/3, then 2 sec2 A + 2 tan2 A -7 =

Answer 1

Answer:

cos A = 2/3, given

let the ratio be k

cos A = 2k/3k

H²=P²+B²

(3k)²=P²+(2k)²

P²= 9k²-4k² = 5k²

P=√5k

2 sec2 A + 2 tan2 A -7 =

2×2×3k/2k +2× 2×√5k/2k -7

=6+2√5-7= -1+2√5