Y = 4X3 - 6X2 + 15X – 19 and Z = 3X2 + 5X - 9. Find the value of (dY/dX) (dZ/dX) when x = 1.
Y = 4X3 - 6X2 + 15X – 19 and Z = 3X2 + 5X - 9. Find the value of (dY/dX) (dZ/dX) when x = 1. Correct Answer <span style="">165</span>
Given:
Y = 4X3 - 6X2 + 15X – 19
Z = 3X2 + 5X - 9
Concept:
If x = yn , then differentiation is dx/dy = nyn - 1
Calculation:
Y = 4X3 - 6X2 + 15X – 19
dy/dx = 12x2 - 12x + 15 ---- (1)
Z = 3X2 + 5X - 9
dz/dx = 6x + 5 ---- (2)
(dy/dx) (dz/dx) = (12x2 - 12x + 15) (6x + 5) (from 1 and 2)
⇒
⇒
⇒ 15 × 11
⇒ 165
∴ The value of (dY/dX) (dZ/dX) when x = 1 is 165.
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Feb 20, 2025