$(1)$ \[ b=\frac{x}{l}b_0 \] $(2)$ \[ I_x=\frac{1}{12}bh^3=\frac{1}{12}\frac{x}{l}b_0h^3 \] $(3)$ \[ x=lで\theta=0,\omega=0 \] $(4)$ \[\begin{align} \frac{d^2y}{dx^2} &=-\frac{M^2}{EI}\\ &=-\frac{1}{EI_x}Wx\\ &=\frac{12l}{Exb_0h^3}Wx\\ &=\frac{12lW}{Eb_0h^3} \end{align}\] \[ \theta=\frac{dy}{dx}=\frac{12lW}{Eb_0h^3}x+C_1\\ x=lで\theta=0より\\ C_1=-\frac{12l^2W}{Eb_0h^3}\\ \therefore\theta=\frac{12lW}{Eb_0h^3}x-\frac{12l^2W}{Eb_0h^3} \] $(5)$ \[ \omega=\frac{6lW}{Eb_0h^3}x^2+C_1x+C_2\\ x=lで\omega=0より\\ C_2=\frac{6l^3W}{Eb_0h^3}\\ \therefore\omega=\frac{6lW}{Eb_0h^3}x^2-\frac{12lW}{Eb_0h^3}x+\frac{6l^3W}{Eb_0h^3} \] $(6)$ \[ x=0を代入して\\ \theta_A=-\frac{12l^2W}{Eb_0h^3} \] $(7)$ \[ x=0を代入して\\ \omega_A=\frac{6l^3W}{Eb_0h^3}\ \]