Three castings are of the same material, volume and cast under similar conditions. One is a sphere, another is a cube and the third is cylinder with its length being equal to its diameter.

The ratio of solidification times of sphere to the cube is

Three castings are of the same material, volume and cast under similar conditions. One is a sphere, another is a cube and the third is cylinder with its length being equal to its diameter.

The solidification time of the sphere to the cylinder

Shell molding is an investment casting process $$(T/F)$$

Given
$$y = \int\limits_1^{{x^2}} {\cos t\,\,\,dt,} $$ $${\,\,\,}$$ then $${{dy} \over {dx}} = \_\_\_\_\_.$$