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Planes

Just a quick question that I know I'll kick myself for not getting...

"Find the acute angle between the planes y=0 and 2x -y - 3z =7."

Answer is x + 2y + 4z = 0 for anyone wondering, thanks. :smile: The y=0 plane is just throwing me and I'm really unsure what to do.
y=0 is the xz plane. I think you need to find 1 line on each plane and use the dot product to find the angle.

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Original post by Blue7195
Just a quick question that I know I'll kick myself for not getting...

"Find the acute angle between the planes y=0 and 2x -y - 3z =7."

Answer is x + 2y + 4z = 0 for anyone wondering, thanks. :smile: The y=0 plane is just throwing me and I'm really unsure what to do.


How can x+2y+4z=0 be an angle?
The usual method of finding the angle between two planers is that it is also the angle between the normals to the planes, so in this case the angle between (010) \begin{pmatrix} 0 \\ 1 \\ 0 \end{pmatrix} and (213)\begin{pmatrix} 2 \\ -1 \\ -3 \end{pmatrix}
Reply 3
Original post by brianeverit
How can x+2y+4z=0 be an angle?
The usual method of finding the angle between two planers is that it is also the angle between the normals to the planes, so in this case the angle between (010) \begin{pmatrix} 0 \\ 1 \\ 0 \end{pmatrix} and (213)\begin{pmatrix} 2 \\ -1 \\ -3 \end{pmatrix}


Sorry I posted this a little late and never even realised :colondollar:

Thanks a lot for your help though! Got it now :smile:
Original post by Blue7195
Sorry I posted this a little late and never even realised :colondollar:

Thanks a lot for your help though! Got it now :smile:


No problem. Glad to help.

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