Answer:
<em>Hey there Marcus! LOL Anyways.. this answer would be..</em> It is one-half the area of a rectangle of length 4 units and width 5 units.
Square root of 15 because you don't know what know is going to go after it, unlike the others where you can guess the numbers that goes after it
Cos( A + B ) = cosAcosB - sinAsinB ;
cos( A + B ) / ( cosAsinB ) = ( cosAcosB - sinAsinB ) / ( cosAsinB ) = ( cosAcosB ) / ( cosAsinB ) - ( sinAsinB ) / ( cosAsinB ) = cosB / sinB - sinA / cosA = cotB - tanA ;
