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Exercise 1919Calculus › Multivariable calculus › Vector calculusL1Added 3 Nov 2026

Finding a potential function

#potential#conservative#integration

Statement

Find a potential for F⃗(x,y)=(excos⁡y, −exsin⁡y)\vec F(x,y)=(e^x\cos y,\,-e^x\sin y).

Hint

Integrate P=excos⁡yP=e^x\cos y in xx, then use the condition on QQ.

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Solution

Integrate PP. ϕ=∫excos⁡y dx=excos⁡y+g(y)\phi=\int e^x\cos y\,dx=e^x\cos y+g(y).

Use QQ. ϕy=−exsin⁡y+g′(y)=−exsin⁡y\phi_y=-e^x\sin y+g'(y)=-e^x\sin y, so g′(y)=0g'(y)=0.

Potential. ϕ(x,y)=excos⁡y\phi(x,y)=e^x\cos y.

Conclusion. F⃗=∇ϕ\vec F=\nabla\phi with ϕ=excos⁡y\phi=e^x\cos y.