Answer:
Option A
Step-by-step explanation:
The response variable is the dependent variable whose variation depends on other variables and in this case it is the type of surgery either total knee replacement or partial knee replacement.
While the explanatory variable which is the independent variable manipulated by the researcher for the given experimental study is the amount of activity the patients were able to do after their respective surgeries.
8 I guess? The question isn’t very well written
x= 90° - 63° = 27° (NO perpendicular to AOB)
angle DOB = (90°+90°) -128° (angles on a straight line)
= 180° - 128°
= 52°
y= 180° - x - 63° - angle DOB (angles on a straight line)
=180° - 27° - 63° - 52°
= 38°
I'm not sure of the answer tho^^ good luck!
Substitute

, so that

. The integral is then equivalent to

Then transforming back to

gives