A function f is defined by f(x)=∫0πcostcos(x−t)dt, where 0≤x≤2π. Which of the following hold good?
(1) f(x) is continuous but not differentiable in (0,2π)
(2) The maximum value of f is π
(3) There exists at least one c∈(0,2π) such that f′(c)=0
(4) The minimum value of f is −2π