For the principal values, evaluate each of the following:
{Since 
An angle in 
whose sine is x,
Similarly, 
An angle in [0,
] whose cosine is x}
Hence,
Principal value of 
is 
5
For the principal values, evaluate each of the following:
{Since An angle in whose sine is x,
Similarly, An angle in [0,] whose cosine is x}
Hence,
Principal value of is