Answer to Credit revision Q 1 a b c sinA sinb sinC == A B C a b c

Answer to Credit revision Q 2 (i)common factor (ii)difference of two squares (iii)trinomial (put in brackets)

Answer to Credit revision Q 4 (i) decide on the 2 quadrants (cos is -ve) (ii) ignore the sign and press INV cos to get angle (iii) work out your 2 angles

Answer to Credit revision Q 3 tan x

Answer to Credit revision Q 6 1

Answer to Credit revision Q 5 m = y 2 – y 1 x 2 – x 1 A(x 1,y 1 ) B(x 2,y 2 ) x y

Answer to Credit revision Q 8 a 2 = b 2 +c 2 -2bccosA A B C a b c

Answer to Credit revision Q 7 For ΔABC, right-angled at A, a 2 = b 2 + c 2 A B C a c b

Answer to Credit revision Q 10 cos A = b 2 + c 2 - a 2 2bc A B C a b c

Answer to Credit revision Q 9 It means there is a root eg x = x

Answer to Credit revision Q 12 x = 5 x = 3 x = 5 x = 0 x = 1

Answer to Credit revision Q 11 x 2 y+y 2xy = x+ y x