The centre and radius of the sphere x2 + y2 + z2 + 3x - 4z + 1 =

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

391.

The number of normals drawn to the parabola y2 = 4x from the point (1, 0) is

  • 0

  • 1

  • 2

  • 3


392.

If the circle x2 + y2 = a intersects the hyperbola xy = cin four points (xi, yi), for i = 1, 2, 3 and 4, then y1 + y2 + y3 + y4 equals

  • 0

  • c

  • a

  • c4


393.

The mid point of the chord 4x - 3y = 5 of the hyperbola 2x- 3y2 = 12 is

  • 0, - 53

  • (2, 1)

  • 54, 0

  • 114, 2


394.

The radius of the sphere x2 + y2 + z2 = 12x + 4y + 3z is

  • 13/2

  • 13

  • 26

  • 52


Advertisement
Advertisement

395.

The centre and radius of the sphere x2 + y2 + z2 + 3x - 4z + 1 = 0 are

  • - 32, 0, - 2; 212

  • 32, 0, 2; 21

  • - 32, 0, 2; 212

  • - 32, 0, 2; 212


C.

- 32, 0, 2; 212

The given equation of sphere is

x2 + y2 + z2 + 3x - 4z + 1 = 0

On comparing this equation with general equation of sphere x2 + y2 + z2 + 2ux + 2vy + 2wz + d = 0,

we get u = 32, v = 0, w = - 2 and d = 1

  Coordinates of centre of sphere              = - u, - v, - w             = - 32, 0, 2and radius of sphere = u2 + v2 + w2 - d             = 94 + 4 - 1             = 9 +124             = 212


Advertisement
396.

Let A and B are two fixed points in a plane, then locus of another point Con the same plane such that CA + CB = constant, (> AB) is

  • circle

  • ellipse

  • parabola

  • hyperbola


397.

The directrix of the parabola y2 + 4x + 3 = 0 is

  • x - 43 = 0

  • x + 14 = 0

  • x - 34 = 0

  • x - 14 = 0


398.

The length of the parabola y2 = 12x cut off by the latusrectum is

  • 62 + log1 + 2

  • 32 + log1 + 2

  • 62 - log1 + 2

  • 32 - log1 + 2


Advertisement
399.

Area enclosed by the curve π4x - 22 + y2 = 8 is

  • π sq unit

  • 2 sq unit

  • 3π sq unit

  • 4 sq unit


400.

The equation of a directrix of the ellipse x216 + y225 = 1 is :

  • 3y = 5

  • y = 5

  • 3y = 25

  • y = 3


Advertisement