If y = mx + 4 is a tangent to both the parabolas, y² = 4x and x² = 2by, then b is equal to:
If y = mx + 4 is a tangent to both the parabolas, y² = 4x and x² = 2by, then b is equal to:
The tangent to the parabola y² = 4ax is y = mx + a/m.
For y² = 4x, a=1. So, the tangent is y = mx + 1/m.
The given line is y = mx + 4.
Comparing the two, 1/m = 4 ⇒ m = 1/4.
The line is y = (1/4)x + 4.
This line is also tangent to x² = 2by.
Substitute y into the parabola equation:
x² = 2b (1/4)x + 4)
x² = (
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->|r1 – r2| < C1C2 < r1 + r2
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4x + 2y – 12 = 0
α + 1.6 = 4 ⇒ α = 2.4
β + 2.8 = 6 ⇒
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Maths Ncert Solutions class 11th 2026
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