This shows you the differences between two versions of the page.
Both sides previous revision Previous revision Next revision | Previous revision | ||
math104-f21:hw15 [2021/12/09 00:49] pzhou |
math104-f21:hw15 [2022/01/11 08:36] (current) pzhou ↷ Page moved from math104:hw15 to math104-f21:hw15 |
||
---|---|---|---|
Line 62: | Line 62: | ||
$$ \int_0^6 x dF(x) = 0 + 1 + \cdots + 6 = .. $$ | $$ \int_0^6 x dF(x) = 0 + 1 + \cdots + 6 = .. $$ | ||
- | 7, 35.4 | + | === 7, 35.4 === |
+ | Since $F(t)$ is differentiable and monotone over that range, we have $dF(x) = F'(x) dx$, with $F'(x) = \cos(x)$ for $t \in [-\pi/2, \pi/2]$. | ||
+ | $$ \int_0^{\pi/ | ||
+ | |||
+ | Alternatively, | ||
+ | $$ \int_a^b f dF = \int_a^b d(f F) - F df = f F|^b_a - \int_a^b F df(x) $$ | ||
+ | Here, in this problem, we have $f(x) = x$, thus | ||
+ | $$ \int_0^{\pi/ | ||