OCR MEI C3 Maths June 2015

Ive been put in for the core 3 exam early and have no clue what im doing frustrated cuz ill definately need to retake next year

Reply 167

chem@uni

OP

9

Original post by lizard54142

Just consider the period of the sin graph.

what is the period of a sin, cos and tan graph?

Reply 168

chem@uni

OP

9

http://www.thestudentroom.co.uk/attachment.php?attachmentid=425525

Anyone know what exam paper that is from?

Reply 169

emi1996

1

Original post by messupp

If x > y then x – y > 0
(x + 0.5y)^2+ (3/4)y^2is greater than 0 since it is the sum oftwo squares
so x^2+ xy + y^2 > 0
Therefore (x – y)(x^2+ xy + y^2) > 0

So x^3– y^3> 0
i.e. x^3> y^3

Thx!

Reply 170

tingirl

How do you know when to use integration by substitution? Is there a rule or do you just use it when you don't think any other method would work?

e.g. how would you know to use substitution for this: (or is there another method that works for this Q?)

Reply 171

Original post by chem@uni

what is the period of a sin, cos and tan graph?

tan\theta = tan(\theta \pm n\pi)

cos\theta = cos(\theta \pm 2n\pi)

sin\theta = sin(\theta \pm 2n\pi)

(edited 8 years ago)

Reply 172

tingirl

Original post by chem@uni

http://www.thestudentroom.co.uk/attachment.php?attachmentid=425525

Anyone know what exam paper that is from?

Jan 2012

Reply 173

Original post by tingirl

How do you know when to use integration by substitution? Is there a rule or do you just use it when you don't think any other method would work?

e.g. how would you know to use substitution for this: (or is there another method that works for this Q?)

You can actually integrate this directly (because it is a linear function in the square root), so you don't need to use a substitution if you don't want to. Rewrite it as

(3x-2)^{-1/2}

Reply 174

chem@uni

OP

9

Original post by lizard54142

tan\theta = tan(\theta \pm n\pi)

cos\theta = cos(\theta \pm 2n\pi)

sin\theta = sin(\theta \pm 2n\pi)

There was a question that wanted you to state an actually answer like 180 degrees??

Reply 175

Original post by chem@uni

There was a question that wanted you to state an actually answer like 180 degrees??

Yeah, I just told you the periods!

Tangent has a period of

\pi

or 180 degrees, Sine and Cosine both have a period of

2\pi

or 360 degrees.

Reply 176

tingirl

Original post by lizard54142

You can actually integrate this directly (because it is a linear function in the square root), so you don't need to use a substitution if you don't want to. Rewrite it as

(3x-2)^{-1/2}

OH YEAH!!! Thanks! I think I get it now - if there was a fraction with

x^2

in the denominator and no

x

in the numerator, you'd use substitution, right?
I hope they just tell us when to use substitution :tongue:

Reply 177