For the function \( f(x)=-6 x^{2}+7 x-1 \), what would the maximum or a minimum be? Enter your answer as a fraction \( \times \) Incorrect. Use \( -\frac{b}{2 a} \) to find the \( x \)-value. Then watch your negatives as you substitute it into \( f(x) \).

(v) The value of \( \int_{-\infty}^{\infty} \delta(t) d t \) is: (a) 0 (b) 1 (c) -1 (d) \( \infty \) (vi) Solution of \( \frac{d^{2} x}{d x^{2}}-k x=0 \), when \( k=0 \) is: (a) \( c_{1} x+c_{2} \) (b) \( c_{1} \cos x+c_{2} \sin x \) (c) \( c_{1} e^{\lambda x}+c_{2} e^{-\lambda x} \) (d) None of these (vii) Equation \( u_{t u}-c^{2} u_{x z}=0 \) is: (a) one dimensional wave equation P.T.O.

Determina expresau a. \( \int 8 x\left(4 x^{2}-3\right) \) b. \( \int 2 t^{-3}\left(4 t^{-2}\right)^{-} \) c. \( \int_{1}^{3}\left(8 x-2 x^{2}\right) \)

50. Determinaţi valorile parametrului real \( m \) pentru care graficul funcțici \( f: R \rightarrow R \), \( f(x)=\sqrt[3]{x^{2}+m x+1} \) are tangentă in fiecare punct \( x \in R \).

The motion of a particle performing damped vibrations is given by \( \gamma=e^{-t} \sin 2 t, \gamma \) being the displacement trom its mean position at time \( t \). Show that \( \gamma \) is a maximum when \( t=\frac{1}{2 \tan ^{-1}(2)} \) and determine this maximum displacement to three significant figures.

The function \( f(x)=\frac{x}{x+1} \) is concave up on