Solve 4sinx + 9cosx = 0 for 0° < x < 360°.
- (a)Solve 4sinx + 9cosx = 0 for 0° < x < 360°.[3]
- (b)Solve cosecy – 1 = 12 siny for 0° < y < 360°.[5]
- (c)Solve 3sec(z/3) = 5 for 0 < z < 6π radians.[4]
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2012). The mark or mark type is shown in brackets.
- [B1] tan x = -2.25
- [B1] 114
- [B1] 294
- [B1] Uses cosec y = 1/sin y
- [M1] Forms quadratic in sin y : 12sin²y + sin y – 1 [= 0]
- [M1] (4sin y-1)(2sin y + 1)[= 0]
- [A1] 14.5 and 199.5
- [A1] 165.5 and 340.5
- [B1] cos(z/3) = 3/5
- [M1] z/3 = 0.927
- [A1] z = 2.78 to 2.79 inc
- [A1] z = 16.1
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