Calculate the length of the curve given by x = e2theta costheta and y = e2theta sintheta for 0 theta pi. Calculate the surface area generated when the curve of y = cosx between x = 0 and x = (pi)/(2) rotates about the x-axis.
|Mathematics
Calculate the length of the curve given by x = e2theta costheta and y = e2theta sintheta for 0 theta pi. Calculate the surface area generated when the curve of y = cosx between x = 0 and x = (pi)/(2) rotates about the x-axis.
ScanSolve AI Answer
Answer
25(e2π−1)
6.1 Calculate the length of the curve given by x=e2θcosθ and y=e2θsinθ for 0≤θ≤π.
Assumption: Based on typical problem complexity for this type of question, it is assumed that the second function is y=e2θsinθ, as y=e2θcosθ would lead to a significantly more complex integral.
Step 1: Find the derivatives dθdx and dθdy.
Given x=e2θcosθ:
dθdx=dθd(e2θcosθ)=(2e2θ)cosθ+e2θ(−sinθ)=e2θ(2cosθ−sinθ)
Given y=e2θsinθ:
dθdy=dθd(e2θsinθ)=(2e2θ)sinθ+e2θ(cosθ)=e2θ(2sinθ+cosθ)
Step 3: Set up the arc length integral.
The arc length formula for parametric curves is L=∫αβ(dθdx)2+(dθdy)2dθ.
L=∫0π5e4θdθ=∫0π5e4θdθ=∫0π5e2θdθ
Step 4: Evaluate the integral.
L=5[21e2θ]0πL=25(e2π−e2(0))L=25(e2π−e0)L=25(e2π−1)
The length of the curve is 25(e2π−1).
6.2 Calculate the surface area generated when the curve of y=cosx between x=0 and x=2π rotates about the x-axis.
Step 1: Find the derivative dxdy.
Given y=cosx:
dxdy=dxd(cosx)=−sinx
Step 3: Set up the surface area integral.
The surface area of revolution about the x-axis is S=∫ab2πy1+(dxdy)2dx.
S=∫02π2π(cosx)1+sin2xdx
Step 4: Use substitution to evaluate the integral.
Let u=sinx. Then du=cosxdx.
When x=0, u=sin(0)=0.
When x=2π, u=sin(2π)=1.
The integral becomes:
S=2π∫011+u2du
This is a standard integral of the form ∫a2+u2du=2ua2+u2+2a2ln∣u+a2+u2∣. Here a=1.
S=2π[2u1+u2+21ln∣u+1+u2∣]01
Step 5: Evaluate the definite integral.
Evaluate at the upper limit u=1:
211+12+21ln∣1+1+12∣=212+21ln(1+2)
Evaluate at the lower limit u=0:
201+02+21ln∣0+1+02∣=0+21ln(1)=0
Subtract the lower limit value from the upper limit value:
S=2π((22+21ln(1+2))−0)S=2π(22+21ln(1+2))S=π2+πln(1+2)
The surface area generated is π2+πln(1+2).
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6.1 Calculate the length of the curve given by x = e^2 and y = e^2 for 0 ≤ ≤ .
Calculate the length of the curve given by x = e2theta costheta and y = e2theta sintheta for 0 theta pi. Calculate the surface area generated when the curve of y = cosx between x = 0 and x = (pi)/(2) rotates about the x-axis.
This mathematics problem involves applying core mathematical principles and formulas. Below you will find a complete step-by-step solution with detailed explanations for each step, helping you understand not just the answer but the method behind it.
ScanSolve AI Answer
6.1 Calculate the length of the curve given by x = e^2 and y = e^2 for 0 ≤ ≤ . Assumption: Based on typical problem complexity for this type of question, it is assumed that the second function is y = e^2 , as y = e^2 would lead to a significantly more complex integral. Step 1: Find the derivatives (dx)/(d) and (dy)/(d). Given x = e^2 : (dx)/(d) = (d)/(d)(e^2 ) = (2e^2) + e^2(-) = e^2(2 - ) Given y = e^2 : (dy)/(d) = (d)/(d)(e^2 ) = (2e^2) + e^2() = e^2(2 + ) Step 2: Calculate ((dx)/(d))^2 + ((dy)/(d))^2. ((dx)/(d))^2 = (e^2(2 - ))^2 = e^4(4^2 - 4 + ^2) ((dy)/(d))^2 = (e^2(2 + ))^2 = e^4(4^2 + 4 + ^2) Summing these: ((dx)/(d))^2 + ((dy)/(d))^2 = e^4(4^2 - 4 + ^2 + 4^2 + 4 + ^2) = e^4(5^2 + 5^2) = 5e^4(^2 + ^2) = 5e^4(1) = 5e^4 Step 3: Set up the arc length integral. The arc length formula for parametric curves is L = _^ sqrt(((dx)/(d))^2 + ((dy)/(d))^2) d. L = _0^ sqrt(5e^4) d = _0^ sqrt(5) sqrt(e^4) d = _0^ sqrt(5) e^2 d Step 4: Evaluate the integral. L = sqrt(5) [ (1)/(2)e^2 ]_0^ L = sqrt(5)2 (e^2 - e^2(0)) L = sqrt(5)2 (e^2 - e^0) L = sqrt(5)2 (e^2 - 1) The length of the curve is sqrt(5)2 (e^2 - 1). 6.2 Calculate the surface area generated when the curve of y = x between x = 0 and x = ()/(2) rotates about the x-axis. Step 1: Find the derivative (dy)/(dx). Given y = x: (dy)/(dx) = (d)/(dx)( x) = - x Step 2: Calculate sqrt(1 + ((dy)/(dx))^2). sqrt(1 + (- x)^2) = sqrt(1 + ^2 x) Step 3: Set up the surface area integral. The surface area of revolution about the x-axis is S = _a^b 2 y sqrt(1 + ((dy)/(dx))^2) dx. S = _0^()/(2) 2 ( x) sqrt(1 + ^2 x) dx Step 4: Use substitution to evaluate the integral. Let u = x. Then du = x \, dx. When x = 0, u = (0) = 0. When x = ()/(2), u = (()/(2)) = 1. The integral becomes: S = 2 _0^1 sqrt(1 + u^2) du This is a standard integral of the form sqrt(a^2 + u^2) du = (u)/(2)sqrt(a^2+u^2) + (a^2)/(2)|u+sqrt(a^2+u^2)|. Here a=1. S = 2 [ (u)/(2)sqrt(1+u^2) + (1)/(2)|u+sqrt(1+u^2)| ]_0^1 Step 5: Evaluate the definite integral. Evaluate at the upper limit u=1: (1)/(2)sqrt(1+1^2) + (1)/(2)|1+sqrt(1+1^2)| = (1)/(2)sqrt(2) + (1)/(2)(1+sqrt(2)) Evaluate at the lower limit u=0: (0)/(2)sqrt(1+0^2) + (1)/(2)|0+sqrt(1+0^2)| = 0 + (1)/(2)(1) = 0 Subtract the lower limit value from the upper limit value: S = 2 ( (sqrt(2)2 + (1)/(2)(1+sqrt(2))) - 0 ) S = 2 ( sqrt(2)2 + (1)/(2)(1+sqrt(2)) ) S = (2) + (1+sqrt(2)) The surface area generated is (2) + (1+sqrt(2)). Last free one today — make it count tomorrow, or type /upgrade for unlimited.