To estimate the area bound by the curves y=2x2+1 and y=x2+1, we first find the difference function f(x):
f(x)=(2x2+1)−(x2+1)=x2
a) Using the trapezium rule with 6 strips from x=2 to x=5.
Step 1: Calculate the width of each strip, h.
The interval is [a,b]=[2,5] and the number of strips n=6.
h=nb−a=65−2=63=0.5
Step 2: Determine the x-coordinates for the ordinates.
x0=2
x1=2+0.5=2.5
x2=2.5+0.5=3
x3=3+0.5=3.5
x4=3.5+0.5=4
x5=4+0.5=4.5
x6=4.5+0.5=5
Step 3: Calculate the corresponding y values using f(x)=x2.
y0=f(2)=22=4
y1=f(2.5)=(2.5)2=6.25
y2=f(3)=32=9
y3=f(3.5)=(3.5)2=12.25
y4=f(4)=42=16
y5=f(4.5)=(4.5)2=20.25
y6=f(5)=52=25
Step 4: Apply the Trapezium Rule formula.
The formula for the Trapezium Rule is:
Area≈2h[(y0+yn)+2(y1+y2+⋯+yn−1)]
Area≈20.5[(4+25)+2(6.25+9+12.25+16+20.25)]
Area≈0.25[29+2(63.75)]
Area≈0.25[29+127.5]
Area≈0.25[156.5]
Area≈39.125
b) Using the mid-ordinate rule with 6 strips from x=2 to x=6.
Step 1: Calculate the width of each strip, h.
The interval is [a,b]=[2,6] and the number of strips n=6.
h=nb−a=66−2=64=32
Step 2: Determine the x-coordinates for the mid-points of each strip.
The mid-points are xi+2h.
m1=2+21(32)=2+31=37
m2=37+32=39=3
m3=3+32=311
m4=311+32=313
m5=313+32=315=5
m6=5+32=317
Step 3: Calculate the corresponding y values using f(x)=x2 at the mid-points.
ym1=f(37)=(37)2=949
ym2=f(3)=32=9
ym3=f(311)=(311)2=9121