Draw
\( A^{\circ} \)
ats
Ask Copilot
2
of 2
ID
(3 marks)
b) By use of principle of mathematical induction prove that
\[
1 \cdot 2+2 \cdot 3+3 \cdot 4+\cdots+n(n+1)=n(n+1)(n+2) / 3
\]
c) Use a truth table to determine whether \( \sim(p \vee(q \rightarrow r)) \leftrightarrow((p \mapsto q) \wedge r) \) a tautology. contradiction or contingency is.
(3 marks)
d) Given that \( f(x)=2 x+5, g(x)=x^{2}-3 \) and \( h(x)=\left\{\begin{array}{ll}x+3 & x \leq 1 \\ x-3 & x>1\end{array}\right. \). Evaluate \( h_{0} g_{a} f_{o} f_{o} g_{o} h_{o} f_{o} h(0) \)
(4 marks)
(2 marks)
c) Show by direct proof that \( x^{2} \) is divisible by 3 , then \( x \) is divisible by 3
(2 marks)
f) Negate the quantifier \( \exists x(P(x) \wedge D(x)) \)
QUESTION THREE ( 20 MARKS )
a) Write the inverse, converse and contrapositive of the following statement "if \( 2+3>7 \), then cows can dance"
(3 marks)
b) Prove that \( \sqrt{p} \), where \( p \) is prime is irrational.
(5 marks)
c) Out of 130 Discrete students, 40 take coffee, 40 take cocoa, 43 take tea, 17 take cocos