Q. Find the area of the region enclosed by the polar curve r=1+cos(θ)
Identify curve type and symmetry: Identify the type of curve and symmetry.The curve given is r=1+cos(θ). This is a cardioid. Since cos(θ) is symmetric about the vertical axis, the curve is symmetric about the θ=0 line.
Set up integral for area: Set up the integral for the area.The area A enclosed by a polar curve from θ=a to θ=b is given by A=21∫(r2)dθ. For a full cardioid, integrate from 0 to 2π.
Substitute curve equation into integral: Substitute the equation of the curve into the integral.Substitute r=1+cos(θ) into the integral. So, A=21∫02π(1+cos(θ))2dθ.
Expand and simplify integrand: Expand the integrand and simplify.(1+cos(θ))2=1+2cos(θ)+cos2(θ). We know the integral of cos(θ) over a full period is 0 and the integral of cos2(θ) over a full period is π. So, A=21∫02π(1+2cos(θ)+cos2(θ))dθ=21[2π+0+π].
Calculate final area: Calculate the final area. A=21[2π+π]=21[3π]=23π.
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