Mathematics
The point P(a, b) is first reflected in the origin and then reflected in the y-axis to P'. If P' has coordinates (3, -4), evaluate a, b.
Reflection
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Answer
We know that,
Rules to find the reflection of a point in the origin :
- Change the sign of abscissa i.e. x-coordinate.
- Change the sign of ordinate i.e. y-coordinate.
∴ Coordinates of point P(a, b) on reflection in origin is (-a, -b).
We know that,
Rule to find reflection of a point in y-axis :
- Change the sign of abscissa i.e. x-coordinate.
- Retain the ordinate i.e. y-coordinate.
∴ Coordinates of point (-a, -b) on reflection in y-axis is (a, -b).
According to question after reflection in y-axis the point is P'(3, -4).
∴ (3, -4) = (a, -b) or, a = 3 and b = 4.
Hence, the value of a = 3, b = 4.
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