DM15, solving quadratic simultaneous equations?

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[DM41] How to change the number of program steps available
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keithdalby
Posts: 477
Joined: Mon Apr 24, 2017 6:38 pm

DM15, solving quadratic simultaneous equations?

Post by keithdalby » Fri Jan 12, 2018 5:28 pm

I have learnt how to solve linear simultaneous equations using matrices on the DM15 and am fairly comfortable with that.

I've learnt how to solve quadratic equations using the SOLVEr on the DM15 and I'm fairly comfortable with that.

Does anyone have any tips for solving simultaneous equations where one is a quadratic? Say,

ax+by=c
ax²+by²=d

to find possible x and y values when the other variables are known?

keithdalby
Posts: 477
Joined: Mon Apr 24, 2017 6:38 pm

Re: DM15, solving quadratic simultaneous equations?

Post by keithdalby » Fri Jan 12, 2018 6:05 pm

Ah, there's a possible solution in the Advanced Solutions handbook but it involves substituting the first equation into the second and using the SOLVEr. I was hoping for a more elegant solution.

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