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Integrals. By Zac Cockman Liz Mooney. Integration Techniques. Integration is the process of finding an indefinite or diefinite integral Integral is the definite integral is the fundamental concept of the integral calculus. It is written as
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Integrals By Zac Cockman Liz Mooney
Integration Techniques • Integration is the process of finding an indefinite or diefinite integral • Integral is the definite integral is the fundamental concept of the integral calculus. It is written as • Where f(x) is the integrand, a and b are the lower and upper limits of integration, and x is the variable of integration.
Integration techniques • Integration is the opposite of Differentiation. • Power Rule • U-Substitution • Special Cases • Sin and Cos
Power Rule • ncannot equal -1 • u=x • Du=dx • N=1 • C = constant • + c
Examples U = 2x Du = dx n = 1 Answer = X2 + C
Examples • Answer = X3/3 + 3x2/2 + 2x + C
Examples • U = 4 X2 • Du = 8xdx • N = -1/2 • 3/8 * 2 * (4x2 + 5)1/2 + C • Answer ¾(4X2 + 5)1/2 + C
Try Me Continue • U = 1 +x2 • Du = 2dx • N = -1/2 • 1/2 [2(1+x2)1/2] + C • (1+x2)1/2 + C
Try Me • U = x4 + 3 • Du = 4x3dx • N = 2
U-Sub • What is U-Sub • When do you use it • Steps • Find your u, du, and for u, solve for x • Replace all the x for u. • Do the same steps for power rule • At the end replace the u in the problem for your u when you found it in the beginning.
Example • U= • X= u2 -1 • dx= 2udu • (u2 – 1) u(2udu) • 2u4 – 2u2 • 2/5 (u5 – 2/3u3) + c • 2/5 (x+1) 5/2 + c
Example • U = • U2 – 1 = x • 2udu = dx 2/3(x+1)3/2 -2(x+1) + c
Try Me U = X = Du = udu 1/10 u5 + 1/2u2 + c 1/10 (2x-3)5/2 + ½(2x-3) + c
Special Cases • When n = -1 the u is put inside the absolute value of the natural log • If there is only one x in the problem and it is squared, square the term before taking the interval
Special Cases • Examples • U = x-1 • Du = dx • N = -1
Special Cases • Examples
Integration using Powers of Sin and Cos • Three Methods • Odd-Even Odd-Odd Even-Even • In Odd-Even, take the odd power and re write the odd power as odd even • Re write the even power change it using Pythagorean identity. • In Odd-Odd, take one of the odds, change to odd even • Use same rules
Integration using Powers of sin and cos • For Even-Even, change the power to the half angle formula. Special Case If the Power of the trig is 1, u is the angle
Powers of Trig Odd - Even • Take the odd power, re write the odd power as odd even • Re write the even power, change it using the Pythagorean identities. • ∫sin5xcos4xdx • ∫sin4x sinxcos4xdx • ∫(1-cos2x)2 sinxcos2xdx
Powers of Trig Odd-Even • ∫(1-2cos2x+cos4x) sinxcos4xdx • ∫sinxcos4xdx-2 ∫sinx cos6xdx+∫sinxcos8xdx -1/5cos5x+2/7cos7x-1/9cos9x+c
Try Me ∫sin32xcos22xdx
Powers of Trig Odd - Even • Try Me • ∫sin32xcos22xdx • ∫sin22xsin2xcos22xdx • ∫(1-cos22x) sin2xcos22xdx • -1/2 ∫sin22xcos22xdx+1/2 ∫sin2xcos42xdx -1/6 cos32x+1/10cos52x+c
Powers of Trig Odd Odd • Take one of the odds, change to odd even. Use other rules to finish. • Example
Powers of Trig Odd-Odd • Example
Powers of Trig Odd Odd • Example Continued
Powers of Trig Even-Even • Change to half angle formula • ∫sin2xdx • ∫1-cos2xdx • 2 • 1/2∫dx-(1/2)(1/2)∫2cos2xdx 1/2x-1/4sin2x+c
Try Me ∫sin2xcos2x
Powers of Trig Even-Even • Try Me • ∫sin2xcos2x • ∫(1-cos2x)(1+cos2x) 2 2 • 1/4∫(1-cos22x)dx • 1/4∫sin22xdx • 1/4∫1-cos4x/2dx • 1/8∫dx-(1/4)(1/8) ∫4cos4xdx • 1/8x-1/32sin4x+c
Solving for Integrals • U =x-1 • Du = dx • N = 2 • 9 – 0 = 9
Try Me • Try Me
Solving for Integrals • U = x2 + 2 • Du = 2xdx • N = 2
Bibliography • www.musopen.com • Mathematics Dictionary, Fourth Edition, James/James, Van NostrandReinnhold Company Inc., 1976