(a) Find y" (0), if y(x) is implicitly defined by x5 + 4y = x + y5 + 3 and y (0) = 1. (b) Given y = (sin x)", find yí
时间: 2024-05-25 08:14:03 浏览: 81
(a) To find y"(0), we will need to differentiate the equation x^5 + 4y = x + y^5 + 3 twice with respect to x and then evaluate at x=0.
Differentiating once, we get:
5x^4 + 4y' = 1 + 5y^4 y'
Differentiating again, we get:
20x^3 + 4y'' = 20y^3 (y')^2 + 20y^3 y''
At x=0, we know y(0)=1, and we can solve for y'(0) by substituting x=0 into the original equation:
0^5 + 4y(0) = 0 + y(0)^5 + 3
4 = 4
Therefore, y'(0) = 0.
To find y"(0), we need to evaluate the expression we found for y'' at x=0 and substitute in y'(0) = 0 and y(0) = 1:
20(0)^3 + 4y"(0) = 20(1)^3 (0)^2 + 20(1)^3 y"(0)
4y"(0) = 0
y"(0) = 0
Therefore, y"(0) = 0.
(b) Given y = (sin x)", we can find y' by differentiating once with respect to x:
y' = (sin x)'
Using the chain rule, we know that (sin x)' = cos x. Therefore, y' = cos x.
To find y", we will differentiate y' with respect to x:
y" = -sin x
Therefore, y' = cos x and y" = -sin x.
阅读全文