If f(x,y)=x2+93y2f(x,y) = x^2 + 93y^2f(x,y)=x2+93y2, what is nablaf\\nabla fnablaf?
langle2,186rangle\\langle 2, 186 \\ranglelangle2,186rangle
langlex,93yrangle\\langle x, 93y \\ranglelanglex,93yrangle
langle2x,186yrangle\\langle 2x, 186y \\ranglelangle2x,186yrangle
langle2x,93yrangle\\langle 2x, 93y \\ranglelangle2x,93yrangle