Fx-cg50 not showing answers in surd form..

My big maths calculator isn’t giving me answers in exact/surd form and it’s completely ****ed me over in the maths exam yesterday.

For example, the Rcos question if you did edexcel asked for R to be an exact value, my calculator gives me 8.246211251 when it should’ve given me 2root17 (which was the correct answer and is completely equal to the decimal I wrote).

Such a stupid way to lose marks, is there anything I can do about this?

Attachment not found

Reply 1

Teribblestudent

14

Can you not press the S->D button or whatever it is?

Reply 2

r3lapse

OP

4

Original post by Teribblestudent

Can you not press the S->D button or whatever it is?

Doesn’t do anything

Reply 3

davros

16

Original post by r3lapse

My big maths calculator isn’t giving me answers in exact/surd form and it’s completely ****ed me over in the maths exam yesterday.

For example, the Rcos question if you did edexcel asked for R to be an exact value, my calculator gives me 8.246211251 when it should’ve given me 2root17 (which was the correct answer and is completely equal to the decimal I wrote).

Such a stupid way to lose marks, is there anything I can do about this?

Attachment not found

Er, why didn't you just work out the exact value without using the calculator?

Reply 4

r3lapse

OP

4

Original post by davros

Er, why didn't you just work out the exact value without using the calculator?

The method I was taught was just working out an alpha value and subbing it back into one of the rcos or rsin equations, gives the same answer

Reply 5

Teribblestudent

14

You could ask your teacher to look at it for you if they know how the calculator works?

Reply 6

jjeeeeeea

12

Is this not normal? Mine does that too, I thought you were supposed to just work it out when it tells you exact form to prevent you skipping a bunch of steps and then check with calculator if you want

Reply 7

r3lapse

OP

4

Original post by jjeeeeeea

Is this not normal? Mine does that too, I thought you were supposed to just work it out when it tells you exact form to prevent you skipping a bunch of steps and then check with calculator if you want

But if it’s the same answer, why doesn’t the calculator give the exact form answer?

Reply 8

jjeeeeeea

12

Original post by r3lapse

But if it’s the same answer, why doesn’t the calculator give the exact form answer?

Yeah, I don't know, it's always bothered me as well :/

Reply 9

davros

16

Original post by r3lapse

The method I was taught was just working out an alpha value and subbing it back into one of the rcos or rsin equations, gives the same answer

Working out R first is almost always the simplest and quickest thing to do, and in an exam they're not going to give you ridiculous numbers - presumably in the exam paper you had 2 numbers to add which gave 68 and the square root of this is

2\sqrt{17}

. You could have written that down faster than typing in the decimal digits from your calculator :smile:

Reply 10

JonahBr

7

I have the same problem right now, me and my dad have the same calculator and for some reason my trig identities are giving decimal answers rather than exact sides despite the fact my dads exact same calculator is giving him surd answers (eg. Sin(45) is giving me 0.707… when it’s giving my dad the exact value of √2/2)

I’m annoyed at the people saying you could just work out the value yourself but that isn’t the point because the calculator is supposed to be able to do that. Not to mention the fact my calculator was doing that fine previously and now it’s not

Reply 11

Carrotsroom

12

Original post by JonahBr

I have the same problem right now, me and my dad have the same calculator and for some reason my trig identities are giving decimal answers rather than exact sides despite the fact my dads exact same calculator is giving him surd answers (eg. Sin(45) is giving me 0.707… when it’s giving my dad the exact value of √2/2)

I’m annoyed at the people saying you could just work out the value yourself but that isn’t the point because the calculator is supposed to be able to do that. Not to mention the fact my calculator was doing that fine previously and now it’s not

have you tried resetting the settings on your calculator? theres options for ways your answer is displayed

Reply 12

JonahBr

7

Original post by Carrotsroom

Original post by JonahBr

I have the same problem right now, me and my dad have the same calculator and for some reason my trig identities are giving decimal answers rather than exact sides despite the fact my dads exact same calculator is giving him surd answers (eg. Sin(45) is giving me 0.707… when it’s giving my dad the exact value of √2/2)

I’m annoyed at the people saying you could just work out the value yourself but that isn’t the point because the calculator is supposed to be able to do that. Not to mention the fact my calculator was doing that fine previously and now it’s not

have you tried resetting the settings on your calculator? theres options for ways your answer is displayed

I’ve tried everything settings wise and in a moment I’m going to resort to a complete factory reset (this weird thing I found online that previously fixed a problem on my calculator that I thought couldn’t be fixed) but there seems to be nothing in the calculators actual system to solve this issue.

Reply 13

JonahBr

7

Original post by Carrotsroom

Original post by JonahBr

I have the same problem right now, me and my dad have the same calculator and for some reason my trig identities are giving decimal answers rather than exact sides despite the fact my dads exact same calculator is giving him surd answers (eg. Sin(45) is giving me 0.707… when it’s giving my dad the exact value of √2/2)

I’m annoyed at the people saying you could just work out the value yourself but that isn’t the point because the calculator is supposed to be able to do that. Not to mention the fact my calculator was doing that fine previously and now it’s not

have you tried resetting the settings on your calculator? theres options for ways your answer is displayed

Yeah I’ve tried that and it didn’t do anything, I’m currently doing the full reset now so I’ll let you know if that works (some weird reset I found by this guy on YouTube so it’s not a well known reset)

Fx-cg50 not showing answers in surd form..

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