Correct option is: B) Sin θ Cos θ
\(Sin^3 \theta \, Cos \theta + Cos^3 \theta \, Sin \theta =\) sin \(\theta\) cos \(\theta\) (\(sin^2\theta + cos^2\theta\))
= sin \(\theta\) .cos \(\theta\) (\(sin^2\theta + cos^2\theta\) = 1)
Correct Answer - C
`I_(1)int_(0)^(pi//2)(cos^(2)x)/(1+cos^(2)x)dx`
`=int_(0)^(pi//2)(cos^(2)(pi//2-x))/(1+cos^(2)(pi//2-x))dx`
`=int_(0)^(pi//2) (sin^(2)x)/(1+sin^(2)x)dx=I_(2)`
Also `I_(1)+I_(2)=int_(0)^(pi//2)((sin^(2)x)/(1+sin^(2)x)+(cos^(2)x)/(1+cos^(2)x))dx`
`=int_(0)^(pi//2)(sin^(2)x+sin^(2)xcos^(2)x+cos^(2)x+sin^(2)xcos^(2)x)/(1+sin^(2)x+cos^(2)x+sin^(2)xcos^(2)x)`
`=int(1+2sin^(2)xcos^(2)x)/(2+sin^(2)x cos^(2)x)dx=2I_(3)`
`:. 2I_(1)=2I_(3)` or `I_(1)=I_(3)` or `I_(1)=I_(2)=I_(3)`
Correct Answer - C
`AB=[(cos^(2) theta,),(cos theta sin theta,)][(cos^(2) phi,cos phi sin phi),(cos phi sin phi,sin^(2) phi)]`
`=[(cos^(2) theta cos^(2) phi+cos theta cos phi sin theta sin phi ,cos^(2)theta cos phi...