Derivatives of functions and rules of differentiation

[jovan leong]

Please help:

4) The gradient of the curve \(\displaystyle \,y\, =\, \dfrac{a}{x}\, -\, \dfrac{b}{x^2}\,\) at the point (1, 7) is -12. Find the value of a and b.

 

[pka]

Please help,
The gradient of the curve y=a/x -b/x² at the point (1,7) is -12. Find the value of a and b.

What is the derivative at that point?

 

[stapel]

4) The gradient of the curve \(\displaystyle \,y\, =\, \dfrac{a}{x}\, -\, \dfrac{b}{x^2}\,\) at the point (1, 7) is -12. Find the value of a and b.

If (x, y) = (1, 7) is on the curve, then you can plug these values into the curve equation to get a linear equation in a and b. What did you get?

If y' = -12 at x = 1, then you can plug these values into the derivative equation to get a second linear equationin a and b. What did you get?

Now you have a system of two linear equations in two variables, which you can solve by using stuff you learned back in algebra. What do you get?

If you get stuck, please reply showing all of your work. Thank you!

 

[jovan leong]

Thank you so much,I've solved the question. Thanks alot