x=f(u)

\int_a^b{\cos{\sqrt{x}}}\ dx=★

u(x)=\sqrt{x}

★=\int_{u(a)}^{u(b)}\cos{u}\cdot 2 u\ du

integrand(u)=\cos(u)\cdot 2u

f(u)=u^2

h(u)=\cos u

u(x) = sqrt(x)
a: 0.5
h_{1}: 0.5
b: 3.5
l1 = Sequence((a + (h_{1} * i), 0), i, 0, 6)
l2 = Sequence(Segment[(a + (h_{1} * i), 0), (a + (h_{1} * i), u(a + (h_{1} * i)))], i, 0, 6)
l3 = Sequence(Segment[(0, u(a + (h_{1} * i))), (a + (h_{1} * i), u(a + (h_{1} * i)))], i, 0, 6)
h(x) = cos(x)
l4 = Sequence((u(a + (h_{1} * i)), 0), i, 0, 6)
l5 = Sequence(Segment[(u(a + (h_{1} * i)), 0), (u(a + (h_{1} * i)), a + (h_{1} * i))], i, 0, 6)
f(x) = x^(2)
l6 = Sequence((u(a + (h_{1} * i)), ((h(u(a + (h_{1} * i))) * 2) * u(a + (h_{1} * i)))), i, 0, 6)
g(x) = cos(sqrt(x))
c = Integral(g, a, b)
integrand(x) = ((cos(x) * 2) * x)
l7 = Sequence(Segment[(u(a + (h_{1} * i)), a + (h_{1} * i)), (u(a + (h_{1} * i)), integrand(u(a + (h_{1} * i))))], i, 0, 6)
f': y = (2 * x)
A = (2.829877825877832, 2.7516921596921544)
B = (3.621412217412225, 2.7516921596921544)
d = Integral(((cos(x) * 2) * x), u(a), u(b))