Question

If x=rsin 0 and y=rcos0 then, the value of x² + y² is:

(a) r

(b) r2

(c) T/ r

(d) 1​

Answer 1

Answer:

option no - r²

Step-by-step explanation:

r

2

Given: x=rsinθcosϕ,y=rsinθsinϕ,z=rcosθ

Now, x

2

+y

2

+z

2

= r

2

sin

2

θcos

2

ϕ+r

2

sin

2

θsin

2

ϕ+r

2

cos

2

θ

= r

2

sin

2

θ(cos

2

ϕ+sin

2

ϕ)+r

2

cos

2

θ

= r

2

sin

2

θ+r

2

cos

2

θ

= r

2

(sin

2

θ+cos

2

θ)

= r

2

Answer 2

r2

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