Evaluate the integral: ${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}{x}^3\sqrt[\phantom{2}]{49-x^2}dx$

$($A$)$ Which trig substitution is correct for this integral?$($B$)$ Which integral do you obtain after substituting for x and simplifying? Hote: to enter theta, type the word theta.$$ d theta$($C$)$ What is the value of the aboven ine....... prms of theta $?$ rrms or$*$G$\_(1)($D$)$ What is the value of the original integral in terms of x $?$

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