I = -425x^2 + 45500x - 650000
For I to be maximum, dI/dx = 0
dI/dx = -850x + 45500 = 0
x = 45500/850 = 53.53
Therefore, maximum I = -425(53.53)^2 + 45500(53.53) - 650000 = 567,794.11
Therefore, <span>the maximum average annual income, in dollars, a lawyer can earn</span> is $567,794
Realize the tangent function has a period of 180°, so when your calculator (or memory) tells you
.. θ = arctan(-1)
.. θ = -45°
you can translate that value into the desired range by adding multiples of 180° to get the two solutions ...
.. θ = 135°
.. θ = 315°
8.6*7=60.2, 16*1.4=22.4, 12*14=168, 7.3*20=146
