Discrete mathematics i. university question hard. q4) provided in the attachment. cheers! : )

(a) Take any point in the plane . To reflect this point in the -axis, you need to negate the -component, so that

(b) This can be done easily by choosing

as

(c) Computing (very easy since it's diagonal) returns the identity matrix , which as a linear transformation returns whatever it is applied to. Geometrically, we're applying the same reflection twice, which returns the original vector to its starting value/position in the plane.

(d) If

then

Multiplying by on the left is equivalent to negating the first row of , and on the right to negative the first column of . The third product is equivalent to negating the antidiagonal.

answer:   28.56 feet (approx)

step-by-step explanation:

since, triangle abc has measure of angle c equal to 55 degrees, measure of angle abc equal to 90 degrees, and length of bc equal to 20 feet.

we have to find out the measurement of segment ab.

therefore, tan 55° =

but bc = 20 feet.

⇒ tan 55 ° =  

⇒ ab = 20 × tan 55 °

⇒ ab = 20 × 1.42814800674

⇒ ab = 28.5629601348   ≈ 28.56 feet