Integration

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For 48, all I did was sub 3, 3.5 ect into the y= equation to get my values... then i subbed those values into the trapezium equation with 0.5 for h...

49.. ahhhh thanks

i did y = 12x + 3, 12x^2+9

b, dy/dx+ -9x , y=-2x^3-9x

What answer do you get for 48?

For 49,
y = 12x + 3 is a correct example of an increasing function.

But y=12x^2+9 isn't a correct example.

For 49b,
y=-2x^3-9x is a correct example of a decreasing function.

But i don't understand what you mean by, dy/dx+ -9x.

Reply 161

username247300

Original post by raheem94

For 48, I got 2.5123.. as a final answer

ok, y = 14x + 14 instead

and dy/dx = -9x , I could always do -x^2 -9

For 50, is it log x against log y?

(edited 12 years ago)

Reply 162

username247300

Original post by raheem94

are you there?

Reply 163

raheem94

Original post by King-Panther

For 48, I got 2.5123.. as a final answer

ok, y = 14x + 14 instead

and dy/dx = -9x , I could always do -x^2 -9

For 50, is it log x against log y?

Original post by King-Panther

are you there?

Yes, i am here, but i am also working on my own work right now, so i am not able to help you.

For 48, you have got the right answer.

For 49a,
Your two examples, y = 12x + 3 and y=14x+14, are correct.

For 49b,
Both are wrong. we don't need to write dy/dx here.

One example can be, y=-2x+1, here the gradient is -2, so its a decreasing function.

I am busy, so can't help you on Q50 now.

Reply 164

username247300

Original post by raheem94

O.k, all i need to know is what to plot (log y against log x?)then i can do the rest myself...

Reply 165

f1mad

Original post by King-Panther

O.k, all i need to know is what to plot (log y against log x?)then i can do the rest myself...

Assuming t and r are constants:
If y= tx^r

logy = logt + rlogx ->

logy = rlogx + logt

Y = MX + C

Yes?

So what can you conclude?

(edited 12 years ago)

Reply 166

username247300

Original post by f1mad

Assuming t and r are constants:
If y= tx^r

logy = logt + rlogx ->

logy = rlogx + logt

Y = MX + C

Yes?

So what can you conclude?

Its going to be a straight line, so I would plot logy against log x?

Reply 167

f1mad

Original post by King-Panther

Its going to be a straight line, so I would plot logy against log x?

Yeah, you would need to convert your values of y into logy and the same for x, for a straight line graph.

Reply 168

username247300

Original post by f1mad

Yeah, you would need to convert your values of y into logy and the same for x, for a straight line graph.

how do you calculate a period in a oscillating sequence?

Reply 169

Zuzuzu

Original post by King-Panther

how do you calculate a period in a oscillating sequence?

The amount of terms before it begins to repeat again.

Reply 170

username247300

Original post by Zuzuzu

The amount of terms before it begins to repeat again.

thanks, is 6,2,-2,6,2,-2,6 periodic and how do i calculate its period?

would 96, -48, 24, -12 geometric....

(edited 12 years ago)

Reply 171

Zuzuzu

Original post by King-Panther

thanks, is 6,2,-2,6,2,-2,6 periodic and how do i calculate its period?

would 96, -48, 24, -12 geometric....

Yes. Use the definition I just gave you to calculate its period.

For the second, is term1/term2 = term2/term3 = term3/term4 etc. If so, you've got a geometric sequence.

Reply 172

username247300

Original post by Zuzuzu

Yes. Use the definition I just gave you to calculate its period.

For the second, is term1/term2 = term2/term3 = term3/term4 etc. If so, you've got a geometric sequence.

for the first on its going down by -4 each time, is that irrelevant and the period is just 3?

Reply 173

Zuzuzu

Original post by King-Panther

for the first on its going down by -4 each time, is that irrelevant and the period is just 3?

Yes.

Reply 174

username247300

Original post by Zuzuzu

Yes.

Ive got 5[2a+9d]

do I multiply just 2a by 5 or 9d as well?

I'm doing Q)3, im assuming i need to do a simultaneous equation due to the two unknowns.

I got it, a=61, d=-2

(edited 12 years ago)

C2_REVIEW_1_SEQUENCES.doc28.7KB