Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

Given that 
y=2x^(4)+1, find 
(d)/(dx)(y^(3)+4cos x) in terms of only 
x.
Answer:

Given that y=2x4+1 y=2 x^{4}+1 , find ddx(y3+4cosx) \frac{d}{d x}\left(y^{3}+4 \cos x\right) in terms of only x x .\newlineAnswer:

Full solution

Q. Given that y=2x4+1 y=2 x^{4}+1 , find ddx(y3+4cosx) \frac{d}{d x}\left(y^{3}+4 \cos x\right) in terms of only x x .\newlineAnswer:
  1. Apply Chain Rule: First, we need to apply the chain rule to find the derivative of y3y^3 with respect to xx. The chain rule states that the derivative of a composite function is the derivative of the outer function evaluated at the inner function times the derivative of the inner function. In this case, the outer function is f(u)=u3f(u) = u^3 and the inner function is u=yu = y, where yy is a function of xx.
  2. Derivative of y3y^3: The derivative of the outer function f(u)=u3f(u) = u^3 with respect to uu is 3u23u^2. We will substitute uu with yy to get 3y23y^2.
  3. Derivative of 4cos(x)4\cos(x): Now we need to find the derivative of the inner function yy with respect to xx. Since y=2x4+1y = 2x^4 + 1, the derivative of yy with respect to xx is dydx=ddx(2x4+1)=8x3\frac{dy}{dx} = \frac{d}{dx}(2x^4 + 1) = 8x^3.
  4. Combine Derivatives: Multiplying the derivative of the outer function by the derivative of the inner function, we get the derivative of y3y^3 with respect to xx: (ddx)(y3)=3y2dydx=3y28x3(\frac{d}{dx})(y^3) = 3y^2 \cdot \frac{dy}{dx} = 3y^2 \cdot 8x^3.
  5. Express in Terms of xx: Next, we need to find the derivative of 4cos(x)4\cos(x) with respect to xx. The derivative of cos(x)\cos(x) with respect to xx is sin(x)-\sin(x), so the derivative of 4cos(x)4\cos(x) with respect to xx is 4sin(x)-4\sin(x).
  6. Simplify Expression: Now we can combine the derivatives of y3y^3 and 4cos(x)4\cos(x) to find the derivative of the entire expression y3+4cos(x)y^3 + 4\cos(x) with respect to xx: (ddx)(y3+4cos(x))=(ddx)(y3)+(ddx)(4cos(x))=3y28x34sin(x)(\frac{d}{dx})(y^3 + 4\cos(x)) = (\frac{d}{dx})(y^3) + (\frac{d}{dx})(4\cos(x)) = 3y^2 \cdot 8x^3 - 4\sin(x).
  7. Simplify Expression: Now we can combine the derivatives of y3y^3 and 4cos(x)4\cos(x) to find the derivative of the entire expression y3+4cos(x)y^3 + 4\cos(x) with respect to xx: (d/dx)(y3+4cos(x))=(d/dx)(y3)+(d/dx)(4cos(x))=3y28x34sin(x)(d/dx)(y^3 + 4\cos(x)) = (d/dx)(y^3) + (d/dx)(4\cos(x)) = 3y^2 \cdot 8x^3 - 4\sin(x). Finally, we need to express the derivative in terms of xx only. We know that y=2x4+1y = 2x^4 + 1, so we can substitute yy in the expression 3y28x34sin(x)3y^2 \cdot 8x^3 - 4\sin(x) with 2x4+12x^4 + 1 to get the final derivative in terms of xx: 4cos(x)4\cos(x)11.
  8. Simplify Expression: Now we can combine the derivatives of y3y^3 and 4cos(x)4\cos(x) to find the derivative of the entire expression y3+4cos(x)y^3 + 4\cos(x) with respect to xx: (ddx)(y3+4cos(x))=(ddx)(y3)+(ddx)(4cos(x))=3y28x34sin(x)(\frac{d}{dx})(y^3 + 4\cos(x)) = (\frac{d}{dx})(y^3) + (\frac{d}{dx})(4\cos(x)) = 3y^2 \cdot 8x^3 - 4\sin(x). Finally, we need to express the derivative in terms of xx only. We know that y=2x4+1y = 2x^4 + 1, so we can substitute yy in the expression 3y28x34sin(x)3y^2 \cdot 8x^3 - 4\sin(x) with 2x4+12x^4 + 1 to get the final derivative in terms of xx: 4cos(x)4\cos(x)11. Now we simplify the expression 4cos(x)4\cos(x)22. First, we square 4cos(x)4\cos(x)33 to get 4cos(x)4\cos(x)44. Then we multiply this by 4cos(x)4\cos(x)55 to get 4cos(x)4\cos(x)66. Finally, we subtract 4cos(x)4\cos(x)77 to get the complete expression in terms of xx: 4cos(x)4\cos(x)99.

More problems from Find the roots of factored polynomials