MATH 142 Final Exam: Integration Techniques and Trigonometric Substitutions, Exams of Mathematics

Solutions for various integration problems using trigonometric substitutions in the context of a final exam for math 142. Topics covered include integrals of the form (tan x sec x dx), (sin x cos x dx), and (sin(α ± β) dx), as well as techniques for evaluating definite integrals using upper and lower limits. The document also includes information on finding antiderivatives using substitution and the evaluation of definite integrals using limits.

Typology: Exams

Pre 2010

Uploaded on 10/01/2009

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MATH 142 Final Exam
a2x2x=asin tπ
2tπ
2a2x2=a2a2sin2t=a2cos2t
a2+x2x=atan tπ
2< t < π
2a2+x2=a2+a2tan2t=a2sec2t
x2a2x=asec t0t < π/2if xa
π/2< t πif xax2a2=a2sec2ta2=a2tan2t
Ztanmxsecnx dx
neven u= tan xsec2x= tan2x+ 1
modd u= sec xtan2x= sec2x1
meven and nodd tan2x= sec2x1
Zsinmxcosnx dx
nodd u= sin xcos2x= 1 sin2x
modd u= cos xsin2x= 1 cos2x
meven and neven sin2x=1
2(1 cos 2x)
cos2x=1
2(1 + cos 2x)
sin αcos β=1
2[sin(αβ) + sin(α+β)]
sin αsin β=1
2[cos(αβ)cos(α+β)]
cos αcos β=1
2[cos(αβ) + cos(α+β)]
sin(α+β) = sin αcos β+ cos αsin β
sin(αβ) = sin αcos βcos αsin β
cos(α+β) = cos αcos β+ sin αsin β
cos(αβ) = cos αcos βsin αsin β
sin(2θ) = 2 sin θcos θsin2θ+ cos2θ= 1
Zsinnx dx =1
nsinn1xcos x+n1
nZsinn2x dx
Zcosnx dx =1
ncosn1xsin x+n1
nZcosn2x dx
pf2

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MATH 142 – Final Exam

a^2 − x^2 → x = a sin t − π 2

≤ t ≤ π 2

→ a^2 − x^2 = a^2 − a^2 sin^2 t = a^2 cos^2 t

√ a^2 + x^2 → x = a tan t − π 2 < t < π 2 → a^2 +x^2 = a^2 +a^2 tan^2 t = a^2 sec^2 t

√ x^2 − a^2 → x = a sec t

0 ≤ t < π/ 2 if x ≥ a π/ 2 < t ≤ π if x ≤ a →^ x

(^2) − a (^2) = a (^2) sec (^2) t − a (^2) = a (^2) tan (^2) t

tanm^ x secn^ x dx ⇒

n even → u = tan x → sec^2 x = tan^2 x + 1 m odd → u = sec x → tan^2 x = sec^2 x − 1 m even and n odd → tan^2 x = sec^2 x − 1

sinm^ x cosn^ x dx ⇒

n odd → u = sin x → cos^2 x = 1 − sin^2 x m odd → u = cos x → sin^2 x = 1 − cos^2 x m even and n even →

sin^2 x = 12 (1 − cos 2x) cos^2 x = 12 (1 + cos 2x)

sin α cos β =

[sin(α − β) + sin(α + β)]

sin α sin β =

[cos(α − β) − cos(α + β)]

cos α cos β =

[cos(α − β) + cos(α + β)] sin(α + β) = sin α cos β + cos α sin β sin(α − β) = sin α cos β − cos α sin β cos(α + β) = cos α cos β + sin α sin β cos(α − β) = cos α cos β − sin α sin β sin(2θ) = 2 sin θ cos θ sin^2 θ + cos^2 θ = 1

sinn^ x dx = −

n sinn−^1 x cos x + n − 1 n

sinn−^2 x dx

∫ cosn^ x dx =

n cosn−^1 x sin x + n − 1 n

cosn−^2 x dx

MATH 142 – Final Exam

∣∣ ∣∣

∫ (^) b a

f (x)dx − Mn

∣∣ ∣∣ ≤ (b^ −^ a)

(^3) K 2 24 n^2

∣∣ ∣∣

∫ (^) b a

f (x)dx − Tn

∣∣ ∣∣ ≤ (b^ −^ a)

(^3) K 2 12 n^2

∣∣ ∣∣

∫ (^) b a

f (x)dx − Sn

∣∣ ∣∣ ≤ (b^ −^ a)

(^5) K 4 180(2n)^4

u dv = uv −

v du

∫ (^) b

a

f (x) dx = lim q→ b−

∫ (^) q

a

f (x) dx

du u^2 + a^2

a tan−^1 u a

+ C

du u^2 − a^2

2 a

ln

u − a u + a

∣ +^ C

du √ u^2 + b

= ln

∣∣u + √u (^2) + b

∣∣ + C

√ du a^2 − u^2

= sin−^1 u a

+ C

tan−^1 x =

∑^ ∞

k=

(−1)k 2 k + 1 x^2 k+1^ − 1 ≤ x ≤ 1

(1 + x)m^ = 1 +

∑^ ∞

k=

m(m − 1)...(m − k + 1) k! xk^ − 1 < x < 1 (m 6 = 0, 1 , 2 , ...)

r = r(θ) : dy dx

r cos θ + dr dθ sin θ

−r sin θ +

dr dθ cos θ