Answer:
Step-by-step explanation:
|4r−12| = -(4r-12) when 4r-12< 0
4r< 12 so r<3
Is this the whole question ?
We have the formula (sin x)^2 + (cos x)^2 = 1;
Then, sin α =

cos β =

We apply the formula sin ( α + β ) = sin α x cos β + sin β x cos α = (3/5)x(4/5) + (4/5)x(3/5) = 12/25 + 12/25 = 24/25;