F.4 maths

1) The HCF of x(1-x^2) , x^2(x+1) , x^3+1 is ?
ans: x+1

2) If f(x)=x^3+5x-6 is divisible by x^2+kx+6,then k= ?
ans:3

3) Suppose 10^a =5 and 10^b=3.
express log 24 in terms of a and b.
ans: 3-3a+b

4) If a polynomial f(x) is fivisible by x+2,then f(x+2) is divisible by?
a)x
b)x+4
c)x-2
d)x+2
ans:b


5)
sin^2 0+sin^2 1+sin^2 2+...+sin^2 89=
ans:44.5
pls show clear steps.thz!