Question

Test Your Understanding (I.7.0): cos - sino 4. Find the value of determinant of ?. sin e cos e Victor vis​

Answer 1

Answer:

Applying R

2

→R

2

+4R

1

and R

3

→R

3

+7R

1

we get

∣

∣

∣

∣

∣

∣

∣

∣

3

5

10

−2

0

0

sin3θ

cos2θ+4sin3θ

2+7sin3θ

∣

∣

∣

∣

∣

∣

∣

∣

=0

⇒2[5(2+7sin3θ)−10(cos2θ+4sin3θ)]=0

⇒2+7sin3θ−2cos2θ−8sin3θ=0

⇒2−2cos2θ−sin3θ=0

⇒sinθ(4sin

2

θ+4sinθ−3)=0

⇒sinθ=0 or (2sinθ−1)=0 or (2sinθ+3)=0

⇒sinθ=0 or sinθ=

2

1