Pra calcular a área entre duas curvas, precisa calcular [tex3]\int|f(x)-g(x)|dx[/tex3]
.
- Se [tex3]0\leq x<1[/tex3]
[tex3]f(x)< g(x)\implies f(x)-g(x)<0[/tex3]
- Se [tex3]1\leq x\leq {\pi\over2}[/tex3]
[tex3]f(x)> g(x)\implies f(x)-g(x)>0[/tex3]
Então:
[tex3]\int_0^{\pi\over2}|f(x)-g(x)|dx[/tex3]
[tex3]\int_0^{1}|f(x)-g(x)|dx+\int_1^{\pi\over2}|f(x)-g(x)|dx[/tex3]
[tex3]\int_0^{1}-[f(x)-g(x)]dx+\int_1^{\pi\over2}[f(x)-g(x)]dx[/tex3]
[tex3]-\int_0^{1}[f(x)-g(x)]dx+\int_1^{\pi\over2}[f(x)-g(x)]dx[/tex3]
[tex3]-[\sen(x)(x-1)+\cos(x)]^1_0+[\sen(x)(x-1)+\cos(x)]^{\pi\over2}_1dx[/tex3]
[tex3]-[\sen(1)(1-1)+\cos(1)-\{\sen(0)(0-1)+\cos(0)\}]+\sen\left({\pi\over2}\right)\left({\pi\over2}-1\right)+\cos\left({\pi\over2}\right)-[\sen(1)(1-1)+\cos(1)][/tex3]
[tex3]-[\cos(1)-1]+{\pi\over2}-1-\cos(1)[/tex3]
[tex3]-\cos(1)+1+{\pi\over2}-1-\cos(1)[/tex3]
[tex3]{\pi\over2}-2\cos(1)[/tex3]