Question

Find the identical expression for cos(A+B) /sinAcosB

Answer 1

EXPLANATION

Apply the fraction rule:

`(a\pm b)/(c)=(a)/(c)\pm(b)/(c)`
`(\sin(a)+\sin(b))/(\sin(a)\cos(b))=(\sin(a))/(\sin(a)\cos(b))+(\sin (b))/(\sin (a)\cos (b))`
`=(\sin(a))/(\sin(a)\cos(b))+(\sin (b))/(\sin (a)\cos (b))`

Cancel:

`(\sin (a))/(\sin (a)\cos (b))`

Cancel the common factor: sin(a)

`(1)/(\cos (b))`
`=(1)/(\cos(b))+(\sin (b))/(\sin (a)\cos (b))`