Question

. Find the value of n ѕо thаt V= r" (3 cos2 0 - 1) satisfies a 2 а) 1 д + sin өдө ОЙ sin e дө = 0. де де​

Answer 1

Answer:

orrect option is

D

3

Two equations are given in the problem statement

(y+z)cos3θ−(xyz)sin3θ=0⋯ (1)

xyzsin3θ=(2cos3θ)z+(2sin3θ)y⋯ (2)

(xyz)sin3θ=(y+2z)cos3θ+ysin3θ ⋯ (3)

From equation (1) and (2), we get

∴(y+z)cos3θ=(2cos3θ)z+(2sin3θ)y=(y+2z)cos3θ+ysin3θ

y(cos3θ −2sin3θ)=zcos3θ and

From equation (2) and (3)

y (sin3θ −cos3θ) =0⇒sin3θ −cos3θ =0⇒sin3θ =cos3θ

∴3θ =nπ+

4

π