Q37 of 59 Page 178

The point (4, 1) undergoes the following two successive transformations:

(i)Reflection about the line y = x


(ii)Translation through a distance 2 units along the positive x-axis


Then the final coordinates of the point are

Let Q(x, y) be the reflection of P(4, 1) about the line y = x, then midpoint of PQ

which lies on y = x



4 + x = 1 + y


x – y + 3 = 0 …(i)


Now, we find the slope of given equation y = x


Since, this equation is in y = mx + b form.


So, the slope = m = 1


Slope of PQ =


Since, PQ is perpendicular to y = x


And we know that, when two lines are perpendicular then


m1 m2 = -1



y – 1 = - (x – 4)


y – 1 = - x + 4


x + y – 5 = 0 …(ii)


On adding eq. (i) and (ii), we get


x – y + 3 + x + y – 5 = 0


2x – 2 = 0


x – 1 = 0


x = 1


Putting the value of x = 1 in eq. (i), we get


1 – y + 3 = 0


-y + 4 = 0


y = 4


Given that translation through a distance 2 units along the positive x-axis


The point after translation is (1 + 2, 4) = (3, 4)


Hence, the correct option is (b)

More from this chapter

All 59 →