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Conic Sections (Standard)

Multi-step exam-style items.

Phase 2 · Gaokao

Conic Sections: core idea

Focus-directrix.

Example problem: hint and answer

Tangent to x2+y2=25x^2+y^2=25 at (3,4)(3,4): 3x+4y=3x+4y=?

Hint: Standard. Answer: 25.

Practice (9 problems — type your answers)

  • 1. Ellipse x225+y29=1\dfrac{x^2}{25}+\dfrac{y^2}{9}=1: eccentricity e=c/ae=c/a with c=4c=4: ee?

  • 2. Hyperbola x29−y24=1\dfrac{x^2}{9}-\dfrac{y^2}{4}=1: asymptote slope positive?

  • 3. Parabola y2=4axy^2=4ax with a=2a=2: focal length aa?

  • 4. Circle diameter endpoints (0,0),(6,0)(0,0),(6,0): radius?

  • 5. Ellipse major axis length if a=5a=5?

  • 6. Line x=3x=3 intersects x2+y2=25x^2+y^2=25: number of points?

  • 7. Focus-directrix parabola y2=8xy^2=8x: aa?

  • 8. Chord midpoint of x2+y2=r2x^2+y^2=r^2: for midpoint (1,0)(1,0) on unit circle radius? If chord of x2+y2=4x^2+y^2=4 midpoint (1,0)(1,0), half chord length?

  • 9. Normal to y=x2y=x^2 at (1,1)(1,1): slope of normal?

Conic Sections Practice Problems — Standard