Question

Vakra r ka square equal to a square cos2tha

Answer 1

Step-by-step explanation:

Answer

Correct option is

B

(x

2

+y

2

)

2

=a

2

(x

2

−y

2

)

We have x=rcosθ,y=rsinθ

So, r

2

=x

2

+y

2

Given r

2

=a

2

cos2θ

⇒r

2

=a

2

(cos

2

θ−sin

2

θ)

⇒r

2

=a

2

(

r

2

x

2

−

r

2

y

2

)

⇒(r

2

)

2

=a

2

(x

2

−y

2

)

⇒(x

2

+y

2

)

2

=a

2

(x

2

−y

2

)