Let \(L\), be the line \(\frac{x+1}{2}=\frac{y+1}{3}=\frac{z+3}{6}\) and let \(S\) be the set of all points \((a, b, c)\…
Let \(L\), be the line \(\frac{x+1}{2}=\frac{y+1}{3}=\frac{z+3}{6}\) and let \(S\) be the set of all points \((a, b, c)\) on \(L\), whose distance from the line \(\frac{x+1}{2}=\frac{y+1}{3}=\frac{z−9}{0}\) along the line \(L\) is \(7\). Then \(\sum _{(a,\text{ }b,\text{ }c)\in S}(a+b+c)\) is equal
[JEE Main 2026, 22 Jan (Shift 2)]
34
\(\frac{x+1}{2}=\frac{y+1}{3}=\frac{z+3}{6}=\lambda\)
\( x=2 \lambda-1, y=3 \lambda-1 \) & \(z=6 \lambda-3\)
\(\frac{x+1}{2}=\frac{y+1}{3}=\frac{z-9}{0}\)
\( x=2 \mu-1, y=3 \mu-1 \) & \(z=9\)
Let \(M\) is the point of intersection of both given lines
\(\Rightarrow 2\lambda −1=2\mu −1,3\lambda −1=3\mu −1,6\lambda −3=9\)
\(\Rightarrow \lambda =2=\mu\)
\(\Rightarrow \text{M }\left(3,5,9\right)\)
Now let point \(P\) be \(\left(2\text{ K}−1,3\text{ K}−1,6\text{ K}−3\right)\) on \(\text{L}\) such that \(\text{PM}=7\)
\(\Rightarrow \sqrt{{(2\text{K}−4)}^{2}+{(3\text{K}−6)}^{2}+{(6\text{K}−12)}^{2}}=7\)
\(\Rightarrow 49{\text{ K}}^{2}+196−196\text{K}=49\)
\(\Rightarrow {\text{K}}^{2}+4−4\text{K}=1\)
\(\Rightarrow {\text{K}}^{2}−4\text{K}+3=0\)
\(\Rightarrow \text{K}=1,3\)
So points are \(P\left(1,2,3\right)\) or \(P\left(5,8,15\right)\)
So sum of all co-ordinates of \(P = 34\)
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