यदि `cos^(2)x+cos^(4)x=1` हो, तो `tan^(2)x+tan^(4)x` का मान क्या है ?

Options

A. 0
B. 1
C. `2tan^(2)x`
D. `2tan^(4)x`

Answer

b

Explanation

`cos^(2)x+cos^(4)x=1`
`cos^(4)x=1-cos^(2)x`
`cos^(4)x=1 -cos^(2)x`
`cos^(4)x=sin^(2)x`
`cos^(2) x=tan^(2)x` ......(i)
`cos^(4)x=tan^(4)x`
`tan^(2)x+tan^(4)x`
`cos^(2)x+cos^(4)x=1`
(From eq. (i) and (ii))