Inverse trig diff maximisation question (1 Viewer)

[Hehehe22]

I'm pretty sure I'm just overthinking it, but can someone please explain part (c). If you have time, I also need clarification for part (b). Thanks, my brain is fried rn


Cambridge Year 12 Ext 1 Ex. 12A

 

[tywebb]

 

[Hehehe22]

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THANK YOU oh jeez I've lost my mind