∫(0 π) |cosΦ|dΦ
=∫(0 π/2)cosΦdΦ +∫(π/2 π)(-cosΦ)dΦ
=∫(0 π/2)cosΦdΦ -∫(π/2 π) cosΦ dΦ
=sinΦ|(0 π/2) -sinΦ (π/2 π)
=(1 -0) -(0 -1)
=2
∫(0 π) |cosΦ|dΦ
=∫(0 π/2)cosΦdΦ +∫(π/2 π)(-cosΦ)dΦ
=∫(0 π/2)cosΦdΦ -∫(π/2 π) cosΦ dΦ
=sinΦ|(0 π/2) -sinΦ (π/2 π)
=(1 -0) -(0 -1)
=2