Direction Angle, Direction Ratios and Direction Cosine
Three Dimensional Geometry

121159 What is the sum of squares of direction cosines of all the four diagonals of the cube?

1 1
2 2
3 4
4 Cannot be determined as the data is inadequate
Three Dimensional Geometry

121160 \(\quad A(2,3,5), B(\alpha, 3,3)\) and \(C(7,5, \beta)\) are the vertices of triangle. If the median trough \(A\) is equally inclined with the co-ordinate axes, then \(\cos ^{-1}\left(\frac{\boldsymbol{\alpha}}{\boldsymbol{\beta}}\right)=\)

1 \(\cos ^{-1}\left(\frac{-1}{9}\right)\)
2 \(\frac{\pi}{2}\)
3 \(\frac{\pi}{3}\)
4 \(\cos ^{-1}\left(\frac{2}{5}\right)\)
Three Dimensional Geometry

121161 If a line makes angles \(\frac{\pi}{4}\) and \(\frac{\pi}{3}\) with \(Y\)-axis and \(\mathrm{Z}\)-axis respectively, then the obtuse angle made by that line with \(\mathrm{X}\)-axis is

1 \(\frac{\pi}{3}\)
2 \(\frac{2 \pi}{3}\)
3 \(\frac{\pi}{6}\)
4 \(\frac{5 \pi}{6}\)
Three Dimensional Geometry

121162 The direction ratio of the two lines \(A B\) and \(A C\) are \(1,-1,-1\), and \(2,-1,1\). The direction ratio of the normal to the plane \(\mathrm{ABC}\) are

1 2, 3, - 1
2 2, 2, 1
3 \(3,2,-1\)
4 \(-1,2,3\)
Three Dimensional Geometry

121159 What is the sum of squares of direction cosines of all the four diagonals of the cube?

1 1
2 2
3 4
4 Cannot be determined as the data is inadequate
Three Dimensional Geometry

121160 \(\quad A(2,3,5), B(\alpha, 3,3)\) and \(C(7,5, \beta)\) are the vertices of triangle. If the median trough \(A\) is equally inclined with the co-ordinate axes, then \(\cos ^{-1}\left(\frac{\boldsymbol{\alpha}}{\boldsymbol{\beta}}\right)=\)

1 \(\cos ^{-1}\left(\frac{-1}{9}\right)\)
2 \(\frac{\pi}{2}\)
3 \(\frac{\pi}{3}\)
4 \(\cos ^{-1}\left(\frac{2}{5}\right)\)
Three Dimensional Geometry

121161 If a line makes angles \(\frac{\pi}{4}\) and \(\frac{\pi}{3}\) with \(Y\)-axis and \(\mathrm{Z}\)-axis respectively, then the obtuse angle made by that line with \(\mathrm{X}\)-axis is

1 \(\frac{\pi}{3}\)
2 \(\frac{2 \pi}{3}\)
3 \(\frac{\pi}{6}\)
4 \(\frac{5 \pi}{6}\)
Three Dimensional Geometry

121162 The direction ratio of the two lines \(A B\) and \(A C\) are \(1,-1,-1\), and \(2,-1,1\). The direction ratio of the normal to the plane \(\mathrm{ABC}\) are

1 2, 3, - 1
2 2, 2, 1
3 \(3,2,-1\)
4 \(-1,2,3\)
Three Dimensional Geometry

121159 What is the sum of squares of direction cosines of all the four diagonals of the cube?

1 1
2 2
3 4
4 Cannot be determined as the data is inadequate
Three Dimensional Geometry

121160 \(\quad A(2,3,5), B(\alpha, 3,3)\) and \(C(7,5, \beta)\) are the vertices of triangle. If the median trough \(A\) is equally inclined with the co-ordinate axes, then \(\cos ^{-1}\left(\frac{\boldsymbol{\alpha}}{\boldsymbol{\beta}}\right)=\)

1 \(\cos ^{-1}\left(\frac{-1}{9}\right)\)
2 \(\frac{\pi}{2}\)
3 \(\frac{\pi}{3}\)
4 \(\cos ^{-1}\left(\frac{2}{5}\right)\)
Three Dimensional Geometry

121161 If a line makes angles \(\frac{\pi}{4}\) and \(\frac{\pi}{3}\) with \(Y\)-axis and \(\mathrm{Z}\)-axis respectively, then the obtuse angle made by that line with \(\mathrm{X}\)-axis is

1 \(\frac{\pi}{3}\)
2 \(\frac{2 \pi}{3}\)
3 \(\frac{\pi}{6}\)
4 \(\frac{5 \pi}{6}\)
Three Dimensional Geometry

121162 The direction ratio of the two lines \(A B\) and \(A C\) are \(1,-1,-1\), and \(2,-1,1\). The direction ratio of the normal to the plane \(\mathrm{ABC}\) are

1 2, 3, - 1
2 2, 2, 1
3 \(3,2,-1\)
4 \(-1,2,3\)
Three Dimensional Geometry

121159 What is the sum of squares of direction cosines of all the four diagonals of the cube?

1 1
2 2
3 4
4 Cannot be determined as the data is inadequate
Three Dimensional Geometry

121160 \(\quad A(2,3,5), B(\alpha, 3,3)\) and \(C(7,5, \beta)\) are the vertices of triangle. If the median trough \(A\) is equally inclined with the co-ordinate axes, then \(\cos ^{-1}\left(\frac{\boldsymbol{\alpha}}{\boldsymbol{\beta}}\right)=\)

1 \(\cos ^{-1}\left(\frac{-1}{9}\right)\)
2 \(\frac{\pi}{2}\)
3 \(\frac{\pi}{3}\)
4 \(\cos ^{-1}\left(\frac{2}{5}\right)\)
Three Dimensional Geometry

121161 If a line makes angles \(\frac{\pi}{4}\) and \(\frac{\pi}{3}\) with \(Y\)-axis and \(\mathrm{Z}\)-axis respectively, then the obtuse angle made by that line with \(\mathrm{X}\)-axis is

1 \(\frac{\pi}{3}\)
2 \(\frac{2 \pi}{3}\)
3 \(\frac{\pi}{6}\)
4 \(\frac{5 \pi}{6}\)
Three Dimensional Geometry

121162 The direction ratio of the two lines \(A B\) and \(A C\) are \(1,-1,-1\), and \(2,-1,1\). The direction ratio of the normal to the plane \(\mathrm{ABC}\) are

1 2, 3, - 1
2 2, 2, 1
3 \(3,2,-1\)
4 \(-1,2,3\)