1. f(x) = sqrt(2x - 3)
f'(x) = 2/(2*sqrt(2x - 3)) = 1/sqrt(2x - 3) = [x = 2] = 1/sqrt(1) = 1
2. f(x) = sin(2x)
f'(x) = 2*cos(2x) = [x = pi/6] = 2 * 1/2 = 1
3. f(x) = 2*x * cos(x)
f'(x) = 2 * cos(x) - 2*x*sin(x) = [x = 0] = 2
4. f(x)=e^x+5
f'(x) = e^x = [x = ln5] = 5
5 .f(x)=x/1+x^2
f'(x) = ((1 + x^2) - 2*x*x)/(1 + x^2)^2 = [x = 0] = 1