f'(x) = (4 arctan(7x))'
f'(x) = 4 (arctan(7x))'
By the chain rule,
f'(x) = 4/(1 + (7x)^2) * (7x)'
f'(x) = 28/(1 + 49x^2)
and hence
f'(4) = 28/(1 + 49*16) = 28/785
In case you're not sure about the derivative of arctan: If y = arctan(x), then x = tan(y). Differentiating both sides with respect to x gives
1 = sec^2y y' = (1 + tan^2y) y' = (1 + x^2) y'
==> y' = 1/(1 + x^2)
The way u can get ur answer is multiply 17 time 5 then u will get your answer
we have
6+6×8-5÷3+12
so
Applying PEMDAS
P ----> Parentheses first
E -----> Exponents (Powers and Square Roots, etc.)
MD ----> Multiplication and Division (left-to-right)
AS ----> Addition and Subtraction (left-to-right)
step 1
Multiplication
6x8=48
substitute
6+48-5÷3+12
step 2
Division
5÷3=5/3
substitute
6+48-(5/3)+12
step 3
Addition
6+48=54
54-5/3+12
step 4
S
A) 5 feet
all the others are too long