kill(all);

f(x):=(3*x+5)^(1/a);

assume(a > -1)$

'integrate(f(x),x);integrate(f(x),x);

right:(3*x+5)^(1/a+1)/(3*(1/a+1));

forget(a > -1)$ assume(a < -1);

left:integrate(f(x),x);

is(equal(left, right));