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
eydxdy = 2x ⇒ m = dxdy=1+x22x (Q ey = 1 + x2)
| m |= 1+x22∣x∣ Q1+ | x |2 – 2| x | = (1– (| x |))2 ≥ 0
⇒ 1 + | x |2 ≥ 2| x | ∴ |m| ≤ 1