Question

How do you evaluate the expression `sin(u-v)` given `cosu=4/7` with `0<u<pi/2` and `sinv=-9/10` with `pi<v<(3pi)/2`?

Answer 1

`=0.157`

Explanation:

`cosu=4/7`
or
`u=cos^-1(4/7)`
or
`u=55.15^@`
`sinv=-9/10`
or
`v=sin^-1(-9/10)`
or
`v=244.185^@`

Therefore
`u-v`
`=55.15^@-244.185^@`
`=-189.035`

Hence `sin(u-v)`
`=sin(-189.035)`
`=0.157`