Post on 10-May-2018
Worksheet # 5: Trigonometric Integrals
1. What are the three Pythagorean trigonometric identities?
2. What are the power reduction (half angle) formulas for sin2 x and cos2 x?
3. Evaluate the following integrals.
(a)
∫cos2(x) dx
(b)
∫sin3 x dx
(c)
∫sin4(x) dx
(d)
∫ π/2
0
sin2 x cos2(x) dx
(e)
∫tan2 x dx
(f)
∫sin3 x cos2 x dx
(g)
∫x2 sinx dx
(h)
∫sinφ
cos3 φdφ
(i)
∫tan5 x sec3 x dx
(j)
∫sin 8x cos 5x dx (Hint: Use sum and difference formulas)
(k)
∫1− tan2 x
sec2 xdx
(l)
∫t sec2(t2) tan4(t2) dt
(m)
∫ π2
π4
cot3 x dx
(n)
∫sec3 x dx (Hint: Start out using integration by parts with u = secx)
4. Prove that for m,n integers
1
π
∫ 2π
0
cos (mx) cos (nx) =
{0 m 6= n1 m = n
.
5. Evaluate∫
sinx cosxdx by four methods:
(a) the substitution u = cosx
(b) the substitution u = sinx
(c) the identity sin 2x = 2 sinx cosx
(d) integration by parts