Why don't I have to put the +C after my answer for a definite integral?
When you evaluate a definite integral, we can think about using the "+C" and see what happens. Let's take (INT)2x dx between 2 and 3. We then have [x2+C] between 2 and 3. For x=3 we have 9+C, and for x=2 we have 4+C. To evaluate the integral we subtract the lower limit from the upper one so we have (INT)2x dx = (9+C) - (4+C) =9+C-4-C =5. So generally, we can say that when we evaluate a definite integral, the constant terms cancel out so we don't usually bother to write them down.
JC
Related Maths A Level answers
All answers ▸Determine the tangent to the curve y = sin^2(x)/x at the point, x = pi/2. Leave your answer in the form ax+by+c=0
Find an expression in terms of powers of cos(x) for cos(5x)
Show that 2(1-cos(x)) = 3sin^2(x) can be written as 3cos^2(x)-2cos(x)-1=0.
The quadratic equation x^2 + 4kx+2(k+1) = 0 has equal roots, find the possible values of k.