Edexcel A2 C3 Mathematics 12th June 2015

Hello! I'm doing some worksheets ready for the exam, (solomon Worksheet B - Differentiation) and I'm struggling to simplify the equations when they involve 'e' and 'ln' - has any one got any tips/ suggestions on this? For example,

y= 5e^x-3lnx
dy/dx= 5e^x-3/x

But then I'm trying to work out what Y is if X is 0, which apparently is 3... but I'm just trying to make that leap to understand how Y=3

Reply 504

Original post by Viggi

Hello! I'm doing some worksheets ready for the exam, (solomon Worksheet B - Differentiation) and I'm struggling to simplify the equations when they involve 'e' and 'ln' - has any one got any tips/ suggestions on this? For example,

y= 5e^x-3lnx
dy/dx= 5e^x-3/x

But then I'm trying to work out what Y is if X is 0, which apparently is 3... but I'm just trying to make that leap to understand how Y=3

Hi, you can't have x=0 in that because there is an asymptote for the ln part. You can also see the differential doesn't exist there because 3/x

Reply 505

Ripper Phoenix

17

Original post by Viggi

Hello! I'm doing some worksheets ready for the exam, (solomon Worksheet B - Differentiation) and I'm struggling to simplify the equations when they involve 'e' and 'ln' - has any one got any tips/ suggestions on this? For example,

y= 5e^x-3lnx
dy/dx= 5e^x-3/x

But then I'm trying to work out what Y is if X is 0, which apparently is 3... but I'm just trying to make that leap to understand how Y=3

are you sure abt x being 0 because ln0 is a math error/assymptote

Reply 506

https://4738aa85dc81f6cb672cd1f6a9985b3c87922ff3.googledrive.com/host/0B1ZiqBksUHNYVVdvc0h3MEZVb28/C3%20Differentiation%20B%20-%20Questions.pdf

I think I'm doing it wrong then - is there any chance you can give me some help? It's question 2b.

Reply 507

Ripper Phoenix

17

Original post by Viggi

https://4738aa85dc81f6cb672cd1f6a9985b3c87922ff3.googledrive.com/host/0B1ZiqBksUHNYVVdvc0h3MEZVb28/C3%20Differentiation%20B%20-%20Questions.pdf

I think I'm doing it wrong then - is there any chance you can give me some help? It's question 2b.

yeah first put Y as 0 to get the x coordinate of R. This will be in terms of e. After this find length OQ AND PR Then use 0.5(b-a)x height(OR)

Reply 508

I haven't checked, but this should be right.

Reply 509

I know I'm going to sound dumb - so with the equation y= (5e-3)x + 3, the '+3' is the y intercept...? is that the same as being the y coordinate??

Reply 510

how does 6lnx-4x^1/2=0 become x=20-24ln2??

Reply 511

Original post by Viggi

I know I'm going to sound dumb - so with the equation y= (5e-3)x + 3, the '+3' is the y intercept...? is that the same as being the y coordinate??

Yep. It's in the form y=mx+c but the m (gradient) is skanky looking

Reply 512

JaySP

Original post by rayquaza17

You're not allowed a calculator like that in your exam!!

Original post by samb1234

Yes you are. You can't have a calculator that does symbolic calculus but numerical is fine

Posted from TSR Mobile

Original post by Krollo

Fx 991es?

Posted from TSR Mobile

Original post by samb1234

Yes

Posted from TSR Mobile

Sorry just to confirm, is CASIO 991ES allowed or not?

Reply 513

Guitardude165

2

Original post by JaySP

Sorry just to confirm, is CASIO 991ES allowed or not?

Yep it is

Reply 514