2A=3，A=3/2

When x=0, 3cosφ = 2 and cosφ = 2/3.

T/2=π/w=2, w=π/2, that is, T=4.

Therefore: f (1)+f (2)+...+f (100)

=25(f( 1)+f(2)+f(3)+f(4))

= 25 * 3/2[cos(π/2+φ)+cos(π+φ)+cos(3π/2+φ)+cos(2π+φ)]

= 75/2 *(sinφ-cosφ+sinφ+cosφ)

=0