Write the value of cos−1(cos350∘)−sin−1(sin350∘)
We have
cos−1(cos350∘)−sin−1(sin350∘)
=cos−1{cos(360∘−350∘)}−sin−1{sin(360∘−350∘)} [ ∵sin(360∘−x)=−sinx,cos(360∘−x)=cosx]
=cos−1(cos10∘)−sin−1(sin−10∘)
=10∘−(−10∘)=20∘
∴cos−1(cos350∘)−sin−1(sin350∘)=20∘