Qus : 4 Phrases PYQ 2024 1 If the line a 2 x + a y + 1 = 0 , for some real number a , is normal to the curve x y = 1
then
1 a < 0 2 0 < a < 1 3 a > 0 4 − 1 < a < 1 Go to Discussion Phrases Previous Year PYQ Phrases NIMCET 2024 PYQ Solution
Problem:
The line a 2 x + a y + 1 = 0 is normal to the curve x y = 1 . Find possible values of a ∈ R .
Step 1: Slope of Line
Rewrite: y = − a x − 1 a → slope = − a
Step 2: Curve Derivative
x y = 1 ⇒ d y d x = − y x
Slope of normal = x y
Match Slopes
− a = x y ⇒ x = − a y
Plug into Curve
x y = 1 ⇒ ( − a y ) ( y ) = 1 ⇒ y 2 = − 1 a
For real y , we need a < 0
✅ Final Answer:
a < 0
Qus : 11 Phrases PYQ 2023 2
Find foci of the equation x^2 + 2x – 4y^2 + 8y – 7 = 0
1 (\sqrt[]{5}\pm1,1) 2 (-1\pm\sqrt[]{5},1) 3 (-1,\sqrt[]{5}\pm1) 4 (1,-1\pm\sqrt[]{5}) Go to Discussion Phrases Previous Year PYQ Phrases NIMCET 2023 PYQ Solution
Finding Foci of a Conic
Given Equation: x^2 + 2x - 4y^2 + 8y - 7 = 0
Step 1: Complete the square
⇒ (x + 1)^2 - 4(y - 1)^2 = 4
Rewriting: \frac{(x + 1)^2}{4} - \frac{(y - 1)^2}{1} = 1
This is a horizontal hyperbola with:
Center: (-1, 1)
a^2 = 4 , b^2 = 1
c = \sqrt{a^2 + b^2} = \sqrt{5}
✅ Foci:
(-1 \pm \sqrt{5},\ 1)
[{"qus_id":"3767","year":"2018"},{"qus_id":"4293","year":"2017"},{"qus_id":"11115","year":"2022"},{"qus_id":"11141","year":"2022"},{"qus_id":"11518","year":"2023"},{"qus_id":"11637","year":"2024"},{"qus_id":"11665","year":"2024"},{"qus_id":"10215","year":"2015"},{"qus_id":"10440","year":"2014"},{"qus_id":"10465","year":"2014"},{"qus_id":"10483","year":"2014"}]