Question #2ec24

1 Answer
Nov 23, 2016

Given
sinA=12/13 and A" is not in 1st quadrant"

So A must be in 2nd quadrant

Hence A=sin^-1(12/13)=112.62^@

Again

cosB=3/5 and B" is not in 1st quadrant"

So B must be in 4th quadrant

Hence A=cos^-1(3/5)=306.87^@

So A+B=112.62+306.87=419.49^@

Now (419.49-360)^@=59.49^@

Hence A+B-> In the first quadrant.