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Question

Question: If m is the slope of a tangent to the curve e<sup>y</sup> = 1 + x<sup>2</sup>, then...

If m is the slope of a tangent to the curve ey = 1 + x2, then

A

|m| > 1

B

m < 1

C

|m| < 1

D

|m| ≤ 1

Answer

|m| ≤ 1

Explanation

Solution

eydydx\frac{dy}{dx} = 2x ⇒ m = dydx=2x1+x2\frac{dy}{dx} = \frac{2x}{1 + x^{2}} (Q ey = 1 + x2)

| m |= 2x1+x2\frac{2|x|}{1 + x^{2}} Q1+ | x |2 – 2| x | = (1– (| x |))2 ≥ 0

⇒ 1 + | x |2 ≥ 2| x | ∴ |m| ≤ 1