A maths - Surds
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I think the answer provided in the list is wrong. So, do help me check!
A rectangular block has a square base. The length of each side of the base is (sq.rt 5 - sq.rt 3) m and the volume of the block is ( 4 sq.rt 3 - 2 sq rt. 5). Find , without using a calculator, the height of the block in the form of a sq.rt 3 + b sq. rt 5
the answer writes 8 sq.rt 3 - 3 sq rt.5 whereas I got 3 sq.rt3 + 2 sq.rt 5.
Thank you. (((=
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you are correct
Next time try to use calculator to prove yourself right
When the question says "without using a calculator", it is only for showing of working. It does not mean that you cannot use a calculator to check if you did it correctly.
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Originally posted by eagle:
you are correct
Next time try to use calculator to prove yourself right
When the question says "without using a calculator", it is only for showing of working. It does not mean that you cannot use a calculator to check if you did it correctly.
Thanks for your help! I have one question here, in which my answer doesn't tally with that of the answer sheet's. However, I think both are acceptable. Please help me identify the errors, if any, that I made.Find all the angles between 0 and 5 which satisfy the equation
2tan 2x + sq.rt 3 = 0
range : 0<x<5
0<2x<10
tan 2x = - sq.rt 3 / 2
1. 2x is in 2nd or 4th quadrant.
2. tan-1 (sq.rt 3 /2) = 0.7137243789
3. 2x = 2.4278, 5.5694, 8.7110, 11.852(rej)
.: x = 1.21, 2.78, 4.36
the answer from the marking sheet is 1.13 and 2.70.
I did substitute the numbers and values from my answer and that of the answer sheet's. Both fit into the answer perfectly. I don't think I missed out on any answers since I did not cancel out anything. So, I appeal for your help. ;DDDDDDDDDDDDDDDDDDDD
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The answers I substituted from the answer sheet into my calculator didn't really match leh...
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Originally posted by eagle:
The answers I substituted from the answer sheet into my calculator didn't really match leh...
So are my answers valid? thanks. -
your answers seems right on calculator when I sub back to check
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Errm, could anyone help me with a basic surd question? I am new at A maths, just Sec 3 this year. So heres the question:
If a and b are integers, find the value in the equation,
(a-2√2)(14+b√2)= -14√2
Thanks! :D -
expand
14a +ab√2 - 28√2 -4b = -14√2
14a - 4b=0
ab-28 = -14
solve simultaneously =)
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a = + 2 or -2
b = 7 or -7
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your question should be "a and b are positive integer" or something because the question sounds like you have to reject one set of answer...