Make {p} the subject of the formula D/d=f + p/f - p?
回答 (2)
2017-02-24 5:10 pm
D/d = (f + p) / (f - p)
D (f - p) = d (f + p)
Df - Dp = df + dp
-DP - dp = -Df + df
Dp + dp = Df - df
p(D + d) = Df - df
p = (Df - df) / (D + d)
D (f - p) = d (f + p)
Df - Dp = df + dp
-DP - dp = -Df + df
Dp + dp = Df - df
p(D + d) = Df - df
p = (Df - df) / (D + d)
2017-02-24 7:55 pm
Well,
I will assume the formula is :
D/d = (f + p)/(f - p)
D/d * (f - p) = f + p
Df/d - pD/d = f + p
Df/d - f = pD/d + p
pD/d + p = Df/d - f
p(D/d + 1) = f * (D/d - 1)
p = f * (D/d - 1)/(D/d + 1)
p = f * (D - d)/(D + d)
qed
hope it' ll help !!
I will assume the formula is :
D/d = (f + p)/(f - p)
D/d * (f - p) = f + p
Df/d - pD/d = f + p
Df/d - f = pD/d + p
pD/d + p = Df/d - f
p(D/d + 1) = f * (D/d - 1)
p = f * (D/d - 1)/(D/d + 1)
p = f * (D - d)/(D + d)
qed
hope it' ll help !!
收錄日期: 2021-04-18 16:02:47
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