Question

(1-tanA)² formulae
$(1 + tanA) {}^{2} formulae$
This is the Formulae of sec² Theta
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Answer 1

Answer:

Consider, L.H.S = (1+tanA)

2

+(1−tanA)

2

=1+tan

2

A+2tanA+1+tan

2

A−2tanA

=2(1+tan

2

A) [∵1+tan

2

A=sec

2

A]

=2sec

2

A

=R.H.S

Answer 2

Equilateral triangle

Solve for area

A≈3.9cm²