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some tips............
#Some questions may have cunningly designed elaborate answer choices just to
mislead you, like the following.
Qn. The number of tangents to the curve x2 + y2 = 25 through the point (2,3) is
(1) two, given by -12(x2+y2-25) = (2x + 3y ? 25)2
(2) only one, given by 2x + 3y = 25
(3) 0
(4) four
Ans. The given curve is a circle with origin as centre and radius 5. The given point
(2,3) is at a distance 223+ = 13 < 5, the radius, from the centre; hence the
point is inside the circle and therefore no tangent is possible.
Ans choice: (3)
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#. Verification Technique
Qn. The system of equations???has the solution (x,y,z) =
(1) (2,3,0) (2) (1,2,-3) (3) (0,-1,4) (4) (2,4,1)
Ans. Real solving will be lengthy and not necessary. Verify which set of values satisfies the given equations.
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Moderation Team
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