Question

If f (x) = 3x^2 + 15x + 5, then the approximate value of f (3.02) is A. 47.66 B. 57.66 C. 67.66 D. 77.66

Answer 1

HELLO DEAR,

GIVEN f(x) = 3x² + 15x + 5

f'(x) = 6x + 15

we know, f(x + ∆x) - f(x) = f'(x)*∆x

we may write, 3.02 = (3 + 0.02)
put x = 3 , ∆x = 0.02

f(3 + 0.02) - f(3) = (6x + 15)*(0.02)

since, x = 3

f(3.02) = 3(3)² + 15(3) + 5 + (6*3 + 15)(0.02)

f(3.02) = 27 + 45 + 5 + (33)(0.02)

f(3.02) = 77 + 0.66

f(3.02) = 77.66

hence, OPTION (D) is correct.

I HOPE IT'S HELP YOU DEAR,
THANKS