alevel

[fresh fox]

question 7 part b idk why they get a answer 057

also i need help with this question

[stoic wing]

,rotate

[stoic wing]

@fresh fox the bearing of B -> L is the reciprocal of the bearing of L -> B
so 200-180 = 20
therefore A from B = 20 + <LBA (found with sine rule)

sketch a diagram if confused

[grave wadi]

A is 10 km at 080, so it ends up far east of l
B is 6.5 km at 200, so it’s southwest of l. work out the east north coordinates of each, then subtract to get the direction from B to A.That direction has a positive east and positive north component, so it’s in the ne quadrant. Do arctan(east/north) and you get about 57°.

therefore the bearing of A from B is 057

[grave wadi]

for part a, cos(kx) = 0.5
cos(θ) = 0.5 when θ = 60 and 300 each cycle

As x goes 0 to 360, kx goes 0 to 360k, that's k full cycles of cos and each cycle gives two full solutions

so the number of solutions is 2k

For part B, you're required to sketch it but

You can find the period by doing 360/1.5=240

And the y-interceot f(0)=1

x intercepts: solve 1.5x=90,270

so x=60,180

Minimum: at 1.5x=180 so x=120

Part c basically links to part a

kx runs from 0 to 360k.
In gat interval, cos hits 0.5 at 2 values per cycle so normally roots is 2k but we need 3 exact roots and so 2k must sit between 2 and 4..and then simplify the interval

(by ÷2 to get k on its own)

@fresh fox

[fresh fox]

couldu draw diagram cause this is what im getting cause this is what im getting