In this question the need is to simplify both the equations first individually and then after certain amount of simplfication equating both of them.
STEP 1
Divide the first equation throughout by cos
2
.
Then, the equation will be:
a tan
2
+ b = m(1 + tan
2
)
By, simplyfication:
(a – m) tan
2
= m – b.......(3)
STEP 2
Divide the first equation throughout by cos
2
.
Then, the equation will be:
b tan
2
+ a = n(1 + tan
2
)
By, simplyfication:
(b – n) tan
2
= n-a ........(4)
STEP 3
Simplification of condition given:
a tan

= b tan

tan
2
/tan
2
= b
2/a
2…......(5)
STEP 4
Divide equations (3) and (4), then inject the equation (5) in the new equation:
(a – m)(b2)(n – a) = (m – b)(a2)(b – n)
ab2n – mnb2 – a2b2 + amb2 = amb2 – a2mn – a2b2 + a2bn
ab2n + a2mn – mnb2 – nba2 = 0
a2n(m – b) + b2n(a – m) = 0
a2n (m – b)= b2n(m – a)
THE FINAL EQUATION IS:
a2/b2=(m-b)/(m-a)