Question #674da

1 Answer
Nov 25, 2016

d/dxint_0^(2x)(e^t+2t)dt=2e^(2x)+8xddx2x0(et+2t)dt=2e2x+8x

Explanation:

d/dxint_0^(2x)(e^t+2t)dt = d/dx[int_0^(2x)e^tdt+int_0^(2x)2tdt]ddx2x0(et+2t)dt=ddx[2x0etdt+2x02tdt]

=d/dx[(e^t)_0^(2x)+(t^2)_0^(2x)]=ddx[(et)2x0+(t2)2x0]

=d/dx(e^(2x)-e^0+(2x)^2-0^2)=ddx(e2xe0+(2x)202)

=d/dx(e^(2x)+4x^2-1)=ddx(e2x+4x21)

=2e^(2x)+8x=2e2x+8x


Note that we could have avoided calculating the integral and derivatives by letting F(t) = int(e^t+2t)dtF(t)=(et+2t)dt, meaning F'(t) = e^t+2t. Then we have

d/dxint_0^(2x)(e^t+2t)dt = d/dx[F(2x)-F(0)]

=2F'(2x)-0

=2[e^(2x)+2(2x)]

=2e^(2x)+8x