1.

If `cos alpha=(2)/(3) and sin beta=(1)/(4)`, then find `cos(alpha-beta)`.

Answer» Given,
`cos alpha=(2)/(3)implies sin alpha=(sqrt(5))/(3)`
`sin beta=(1)/(4)implies cos beta=(sqrt(15))/(4)`
`cos(alpha-beta)= cos alpha* cos beta+ sin alpha* sin beta=(2)/(3)xx(sqrt(15))/(4)+(sqrt(5))/(3)xx(1)/(4)`
`cos(alpha-beta)=(2sqrt(15)+sqrt(5))/(12)`.


Discussion

No Comment Found