Question

If ((sec a + tan a) (sec B+tan )
(sec y + tan y) (sec a - tan a)
(sec ß-tan B) (sec y-tan y)]=k, then
the value of k is:
(a) 2 (b) + 3 (c)+1 (d) 2​

Answer 1

Step-by-step explanation:

Let (secA+tanA)(secB+tanB)(secC+tanC)=x............(i)

∴(secA−tanA)(secB−tanB)(secC−tanC)=x.............(ii)

Multiplying Eqs. (i) and (ii), we get

(sec

2

A−tan

2

A)(sec

2

B−tan

2

B)(sec

2

C−tan

2

C)=x

2

...........(sec

2

A−tan

2

A)=1

or x

2

=1 ∴ x=±1

Hence, each side is equal to ±1