Compute Δy and dy for the given values of x and dx = Δx.
y = x2 - 6x, x = 5, Δx = 0.5
Solution:
Let y = f(x) = x2 - 6x --- equation(1)
∵ Δy = f (x + Δx) - f(x)
Substitute the values of x = 5, Δx = 0.5
= f(5 + 0.5) - f(5)
= f(5.5) - f(5)
By substituting the values in the equation (1) and simplifying it, we get
Δy = 5.52 - 6(5.5) - [52 - 6(5)]
= - 2.75 - (- 5)
Δy = 2.25
Differentiating both sides of equation (1) with respect to ‘x’.
dy = f’(x) = 2x - 6 dx
Substitute the values of x = 5 and dx = Δx = 0.5
dy = f’(5) = [2(5) - 6] (0.5)
= 4(0.5)
dy = 2
Δy = 2.25 and dy = 2
Compute Δy and dy for the given values of x and dx = Δx.
y = x2 - 6x, x = 5, Δx = 0.5
Summary:
The values of Δy and dy for the given values of x and dx = Δx.
y = x2 - 6x, x = 5, Δx = 0.5 is 2.25 and 2 respectively.
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