Question

If `(x) = 3x^2 + 15x + 5`, then the approximate value of `f(3.02)` is

विकल्प

• 47.66

• 57.66

• 67.66

• 77.66

Answer 1

77.66

Explanation:

`x + Δx` = 3.02, where `x` = 3, `Δx` = 0.02

`Δf(x) = f(x + Δx) - f(x)`

= `f(x) + f^'(x)  phi  Δ x`  ......(1)

Now, `f(x) = 3x^2 + 15x + 5`

`f(3)` = 3.3² + 15.3 + 5 = 27 + 45 + 5 = 77

`f^'(x) = 6x + 15`

`f^'(x) = 6 xx 3 + 15` = 18 + 15 = 33

 Putting there values in (1)

∴ `f(3.02) = 87 + 33 xx 0.02` = 77 + 0.66 = 77.66