If the common tangent to the parabolas y² = 4x and x² = 4y also touches the circle, x² + y² = c², then c is equal to

Option 1 - <p>1/(2√2)</p>
Option 2 - <p>1/√2</p>
Option 3 - <p>1/2<br>&lt;!-- [if !supportLineBreakNewLine]--&gt;<br>&lt;!--[endif]--&gt;</p>
Option 4 - <p>1/4<br>&lt;!-- [if !supportLineBreakNewLine]--&gt;<br>&lt;!--[endif]--&gt;</p>
11 Views|Posted 5 months ago
Asked by Shiksha User
1 Answer
A
5 months ago
Correct Option - 2
Detailed Solution:

y² = 4x and x² = 4y
any tangent of y² = 4x is y = mx + 1/m
it also tangent for x² = 4y
1/m = -m² ⇒ m = -1
∴ common tangent is y = -x - 1, it also touches x² + y² = c²
∴ 1 = c² ⋅ (1+1) ⇒ c² = 1/2

Thumbs Up IconUpvote Thumbs Down Icon

Similar Questions for you

If two circles intersect at two distinct points

->|r1 – r2| < C1C2 < r1 + r2

| r – 2| <  9 + 1 6 < r + 2

|r – 2| < 5                     and r + 2 > 5

–5 < r – 2 < 5                    r > 3                      … (2)

–3 < r < 7                                                        … (1)

From (1) and (2)

3 < r < 7

...Read more

x2 – y2 cosec2q = 5 x 2 1 y 2 s i n 2 θ = 5                        

x2 cosec2q + y2 = 5  x 2 s i n 2 θ + y 2 1 = 5        

e H = 7 e e                  

and e H = 1 + s i n 2 θ 1 &n

...Read more

Slope of axis = 1 2

y 3 = 1 2 ( x 2 )              

2y – 6 = x – 2

2y – x – 4 = 0

2x + y – 6 = 0

4x + 2y – 12 = 0

            α + 1.6 = 4 α = 2.4

            β + 2.8 = 6

...Read more

Taking an Exam? Selecting a College?

Get authentic answers from experts, students and alumni that you won't find anywhere else.

On Shiksha, get access to

66K
Colleges
|
1.2K
Exams
|
6.9L
Reviews
|
1.8M
Answers

Learn more about...

Maths Ncert Solutions class 11th 2026

Maths Ncert Solutions class 11th 2026

View Exam Details

Most viewed information

Summary

Share Your College Life Experience

Didn't find the answer you were looking for?

Search from Shiksha's 1 lakh+ Topics

or

Ask Current Students, Alumni & our Experts

Have a question related to your career & education?

or

See what others like you are asking & answering