Originally Posted by

**shinhidora** I'm back and stuck once again...

Calculate the surface between $\displaystyle y = (1/2)x^2+1$ and $\displaystyle y = -x+4$ between $\displaystyle [0,2.5]$

It's supposed to be $\displaystyle 2.059$

Though I don't get there...

I did, using my TI-84 Plus Calculator:

$\displaystyle y1 = (1/2)x^2 + 1$

2nd + Trace --> 7) $\displaystyle f(x)dx$

Lower Limit: 0

Upper Limit: 2.5

Gives $\displaystyle 5.1041667$

$\displaystyle y2 = -x+4$

2nd + Trace --> 7) $\displaystyle f(x)dx$

Lower Limit: 0

Upper Limit: 2.5

Gives $\displaystyle 6.875$

$\displaystyle 6.875 - 5.104... = 1.4408333$

Anyone got an idea?