- #1
shelovesmath
- 60
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2r(s^2+1)dr + (r^4 + 1)ds = 0
2.book answer different than mine...book's answer: r^2 + s = c(1 -r^2 s)
3. 2r(s^2+1)dr =- (r^4 + 1)ds
-2r/r^4+1 dr = 1/s^2+1 ds
int -2r/r^4+1 dr = int 1/s^2+1 ds
with u substitution on left we have u = -2r, etc.
tan^-1 r^2 = - tan^ -1 s + c
tan^-1 r^2 + tan^-1 s = c
2.book answer different than mine...book's answer: r^2 + s = c(1 -r^2 s)
3. 2r(s^2+1)dr =- (r^4 + 1)ds
-2r/r^4+1 dr = 1/s^2+1 ds
int -2r/r^4+1 dr = int 1/s^2+1 ds
with u substitution on left we have u = -2r, etc.
tan^-1 r^2 = - tan^ -1 s + c
tan^-1 r^2 + tan^-1 s = c
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