Question

solve the problem-If cosA=-24/25 and cosB=3/5,where pie is greater than A greater than 3pie/2 and 3pie/2 is greater than B is greater than 2pie.Find sin(A+B) and cos(A+B)?????plz answer the question very quickly.plz....​

Answer 1

cos A = -24/25

and A is in 3Rd quadrant

so, sinA = (-7/25) ,

now , cosB = 3/5

and B is in 4th quadrant

so, sinB = (-4/5)

we have all values now,

simply put in formula,

sin(A+B) = sinAcosB + cosAsinB

cos(A+B) = cosAcosB - sinAsinB

Do it by yourself now,

it's just calculation left .