A piece of wire of length 24 cm is bent to form the perimeter of a sector of a circle of radius rcm. i Show that the area of the sector, Acm², is given by A = 12r - r2.
ii Express A in the form a - (r - b), where a and b are constants.
iii Given that r can vary, state the greatest value of A and find the corresponding angle of the sector.

Aresearch study is studying the effects of a new drug for osteoporosis alzheimer's disease (ad) for women above the age of 65 years. a group of individuals with osteoporosis is randomized into two groups. one group is treated conventionally, and the second group is treated with the new medication. assessments are made at 3, 6, 12, 36, and 48 months. the conventionally treated group is assessed for ad using a serum blood test, and the treatment group is assessed for ad using a pet radiotracer that binds to beta-amyloid plaques. in comparing these 2 trial arms, the authors of the study may encounter which type of bias? a. selection bias on the risk of developing b. measurement bias c. confounding bias d. recall bias e. lead-time bias