The velocity field for flow is given by`vecV=(5x+6y+7z)hati+(6x+5y+9z)hatj+(3x+2y+lambdaz)hatk` and the density varies as `rho = rho_0` exp (-2t). In order that the mass is conserved, the value of `lambda` should be
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no the formula u mention is wrong where is diffferential wr to t