4. Zsuzsanna is a consumer of housing and food with a Cobb-Douglas utility function, that is, U(H,F) = Ha, where a and are positive constants. (a) Will Zsuzsanna increase her consumption amounts of housing and food in proportion to increases in her income (prices held constant)? Justify your answer mathematically. 1 point (b) Will Zsuzsanna spend the same shares of her income on housing and food regardless of their prices or her income? Justify your answer mathematically. 1 point