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c() = * 2. What is the second derivative of +6? 42. b. S"(t) = 10x + Ve +6 d. f"(x)=sx+Ve+ar 3. A rectangle has a perimeter of 640 cm. What dimensions maximize the area of the rectam n. 120 cm, 200 cm c. 100 cm, 220 cm b. 180 cm, 140 cm d. 160 cm, 160 cm 4. For what values of x is feu) = 5x3-1 increasing? c.x>0 30 b..<1 d. > 1