Find the derivative of the function.
f(x)= x^8√5-3x
f(x)= x^8√5-3x
f'(x) = 8x^7√5-3
but the ans is f(x)= x^7(80-51x)/2√5-3x
If you mean f(x) = x^8√(5-3x), then
f'(x)
= (8x^7)*√(5-3x) + (-3/2)*(x^8) / √(5-3x)
am lost
thanks jai
To find the derivative of the function f(x) = x^8√5 - 3x, we need to apply the product rule and the power rule of differentiation.
The product rule states that if we have a function u(x) multiplied by a function v(x), the derivative of the product is given by the formula:
(fg)'(x) = f'(x)g(x) + f(x)g'(x)
In this case, we have u(x) = x^8√5 and v(x) = -3x. Applying the product rule, we obtain:
f'(x) = (x^8√5)' * (-3x) + (x^8√5) * (-3x)'
Now let's find the derivatives of each term using the power rule. The power rule states that if we have a function of the form f(x) = x^n, the derivative is given by:
f'(x) = nx^(n-1)
Applying the power rule, we have:
(x^8√5)' = 8√5 * x^(8√5 - 1) = 8√5 * x^(8√5 - 1)
And (-3x)' = -3
Substituting these results back into the original formula, we get:
f'(x) = 8√5 * x^(8√5 - 1) * (-3x) + (x^8√5) * (-3)
Simplifying this expression yields the derivative of the function f(x).
Recall the chain rule. If two expressions which are functions of x are multiplied, we do the following:
h(x) = f(x)*g(x)
h'(x) = f'(x)*g(x) + f(x)*g'(x)
As we can see, the derivative of h(x) is the derivative of f(x) multiplied by the original g(x), plus the derivative of g(x) multiplied by the original f(x).
For example,
h(x) = 2x * ln(x)
We know that
derivative of 2x = 2, and
derivative of ln(x) = 1/x. Thus
h'(x) = 2*ln(x) + (2x)*(1/x)
In the problem, f(x) = x^8√(5-3x). We can rewrite this as,
f(x) = (x^8) * (5-3x)^(1/2)
We know that
the derivative of x^8 = 8x^7
the derivative of (5-3x)^(1/2) = (1/2)(-3)(5-3x)^(-1/2)
Using chain rule, you'll get
f'(x) = (8x^7)*(5-3x)^(1/2) + (x^8)*(-3/2)*(5-3x)^(-1/2)
If you simplify this, you'll get the answer that you typed in there:
f'(x) = x^7(80-51x) / 2√(5-3x)
Hope this helps :)