Vectors and matrices — Question 6
QCAA 2022, Paper 1 · 1 mark
Q6 · 2022 · Technology-freeSimple familiar1 mark
QUESTION 6
The Cartesian equation for a sphere with centre (−2,3,−4) and radius 9 is (A)(x−2)2+(y+3)2+(z−4)2=9 (B)(x+2)2+(y−3)2+(z+4)2=9 (C)(x−2)2+(y+3)2+(z−4)2=81 (D)(x+2)2+(y−3)2+(z+4)2=81 WORKED SOLUTION
Answer D
1 markWorked solution
A sphere with centre (h,k,l) and radius r has equation (x−h)2+(y−k)2+(z−l)2=r2. Substituting (−2,3,−4) and 9 gives (x+2)2+(y−3)2+(z+4)2=81. Worked explanation by QCE Vault; correct option verified against the QCAA answer key.
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