The area of the surface is 144.708
The equation of the given surface is,
z=g(x,y)=xy
Solving the partial derivatives,
∂g∂x=y,∂g∂y=x
Substituting to the formula
S=∬√1+( ∂g∂x)2+(∂g∂y)2dA
Thus,
S=∬√1+(y)2+(x)2dAS=∬√1+x2+y2dA
The region in the XY-plane is defined by the intervals 0≤θ≤2π,0≤r≤4
Converting the integral into polar coordinates,
S=∫2π0∫40√1+r2rdrdθ
Integrating with respect to r
S=∫2π0[13(1+r2)32]40dθ
S=∫2π0(17√173−13)dθ
Integrating with respect to θ
S=(17√173−13)[θ]2π0
S≈144.708
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They are all pretty easy all you do is multiply the cost by the amount of things you buy. For example number 4 your variables are cost (c) and songs (s). Your equation is c•s so $0.99 • s. 50 songs would be .99 • 50 which is $49.50
Answer: 121 kilometers
Step-by-step explanation:
14.99 + .80x (-14.99) = 111.79 (-14.99)
.80x (/.80) = 96.8 (/.80)
x = 121
