T torque New member Joined Oct 26, 2010 Messages 2 Oct 26, 2010 #1 How do I find the differential dy to the function y = x(sqrt(1-x^2)) ? I got it down to y = x(1-x^2) ^ 1/2 but I'm stuck from there. Am I supposed to use the chain rule here for the product rule?
How do I find the differential dy to the function y = x(sqrt(1-x^2)) ? I got it down to y = x(1-x^2) ^ 1/2 but I'm stuck from there. Am I supposed to use the chain rule here for the product rule?
D Deleted member 4993 Guest Oct 26, 2010 #2 torque said: How do I find the differential dy to the function y = x(sqrt(1-x^2)) ? I got it down to y = x(1-x^2) ^ 1/2 but I'm stuck from there. Am I supposed to use the chain rule here for the product rule? Click to expand... \(\displaystyle y \ = \ x * (1 - x^2)^{\frac{1}{2}}\) \(\displaystyle \frac{dy}{dx} \ = \ 1 * (1 - x^2)^{\frac{1}{2}} + x * \frac{1}{2} * (1 - x^2)^{-\frac{1}{2}} * (-2 * x)\) Now simplify the above......
torque said: How do I find the differential dy to the function y = x(sqrt(1-x^2)) ? I got it down to y = x(1-x^2) ^ 1/2 but I'm stuck from there. Am I supposed to use the chain rule here for the product rule? Click to expand... \(\displaystyle y \ = \ x * (1 - x^2)^{\frac{1}{2}}\) \(\displaystyle \frac{dy}{dx} \ = \ 1 * (1 - x^2)^{\frac{1}{2}} + x * \frac{1}{2} * (1 - x^2)^{-\frac{1}{2}} * (-2 * x)\) Now simplify the above......
T torque New member Joined Oct 26, 2010 Messages 2 Oct 26, 2010 #3 I got sqrt(1 - x^2) - x^2 / sqrt(1 - x^2) My book's correct answer is: 1 - 2x^2 / sqrt(1 - x^2) What did I do wrong?
I got sqrt(1 - x^2) - x^2 / sqrt(1 - x^2) My book's correct answer is: 1 - 2x^2 / sqrt(1 - x^2) What did I do wrong?
G galactus Super Moderator Staff member Joined Sep 28, 2005 Messages 7,203 Oct 26, 2010 #4 Use proper grouping symbols. They mean everything. You have \(\displaystyle 1-\frac{2x^{2}}{\sqrt{1-x^{2}}}\) written, when I think you mean \(\displaystyle \frac{1-2x^{2}}{\sqrt{1-x^{2}}}\) You're not wrong. It's the same thing. The book found a common denominator and put it in a different form \(\displaystyle \sqrt{1-x^{2}}-\frac{x^{2}}{\sqrt{1-x^{2}}}=\frac{1-2x^{2}}{\sqrt{1-x^{2}}}\)
Use proper grouping symbols. They mean everything. You have \(\displaystyle 1-\frac{2x^{2}}{\sqrt{1-x^{2}}}\) written, when I think you mean \(\displaystyle \frac{1-2x^{2}}{\sqrt{1-x^{2}}}\) You're not wrong. It's the same thing. The book found a common denominator and put it in a different form \(\displaystyle \sqrt{1-x^{2}}-\frac{x^{2}}{\sqrt{1-x^{2}}}=\frac{1-2x^{2}}{\sqrt{1-x^{2}}}\)