suppose (x^2/26)+(y^2/64)=1 and y(1)=7.88811 Find y'(1) by implicit diffentiation

I get y'=16x/9y but I'm not sure where to go from there to get y'(1)?

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- October 2nd 2011, 06:21 PMCyanBCImplicit differentiation
suppose (x^2/26)+(y^2/64)=1 and y(1)=7.88811 Find y'(1) by implicit diffentiation

I get y'=16x/9y but I'm not sure where to go from there to get y'(1)? - October 2nd 2011, 06:38 PMQuackyRe: Implicit differentiation
Disagree with your differentiation, firstly.

Anyway, you know that so substitute that into the original equation to find the value for x at this point. Then it becomes a case of substitution. - October 2nd 2011, 06:50 PMCyanBCRe: Implicit differentiation
Sorry I typoed

Should have been

(x^2/36)+(y^2/64)=1

Forgive me, but I'm just not making a connection between the information y(1)=7.88811 and the original equation. I know I need to substitue and solve for x, but there's a point in my brain that doesnt want to accept how this should occur.

is it just plug in 7.88811 for y^2 and solve for x? - October 2nd 2011, 07:01 PMskeeterRe: Implicit differentiation
- October 2nd 2011, 07:37 PMCyanBCRe: Implicit differentiation
Thank you both very much. That one was driving me crazy. I just need to relax and think a bit more clearly when I get these.

Solution.

-16x/9y is -16(1)/9(7.88811) or -0.225374364426685

Again, thank you very much!