Question

tan^4 theta+tan^2 theta = 1 then prove that
cos^4 theta+cos^2 theta = 1

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Answer 1

Step-by-step explanation:

Given

tan

4

a

+

tan

2

a

=

1

⇒

(

tan

2

a

+

1

)

tan

2

a

=

1

⇒

sec

2

a

tan

2

a

=

1

⇒

(

1

cos

2

a

)

tan

2

a

=

1

⇒

tan

2

a

=

cos

2

a

⇒

sin

2

a

cos

2

a

=

cos

2

a

⇒

sin

2

a

=

cos

4

a

⇒

1

−

cos

2

a

=

cos

4

a

⇒

cos

4

a

+

cos

2

a

=

Sorry for only one word in each line

hope this answer will help you..

Answer 2

Answer:

Given

tan

4

a

+

tan

2

a

=

1

⇒

(

tan

2

a

+

1

)

tan

2

a

=

1

⇒

sec

2

a

tan

2

a

=

1

⇒

(

1

cos

2

a

)

tan

2

a

=

1

⇒

tan

2

a

=

cos

2

a

⇒sin2acos2a

=cos2a

sin2a=cos4a

⇒1−cos2a=cos4a

⇒

cos

4

a

+

cos

2

a

=

1

Step-by-step explanation:

HOPE IT WILL HELP YOU