Calculus Help

BullyCanadian

Platinum Member
May 4, 2003
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Here is the question. I am gonna go get some help tomorrow, but was wondering if anyone can help me out right now (I know most of you guys are really smart)

Here is question 1
The question is to show that the equation on the left equals the right

EDIT - There is a mistake in the question it should be cos{arctan[sin(arcot x)]} = ....
 

Semidevil

Diamond Member
Apr 26, 2002
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so are we supposed to differentiate something or integrate something? what calculus is this?
 

BullyCanadian

Platinum Member
May 4, 2003
2,026
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71
Originally posted by: Semidevil
so are we supposed to differentiate something or integrate something? what calculus is this?

calc 102 first year science in uni.

yes I believe to differentiate, but i have idea about where to start :S trig makes me scared. I have a tutor ready for tomorrow, but need to get started on this question today.
 

chuckywang

Lifer
Jan 12, 2004
20,133
1
0
Originally posted by: BullyCanadian
Here is the question. I am gonna go get some help tomorrow, but was wondering if anyone can help me out right now (I know most of you guys are really smart)

Here is question 1
The question is to show that the equation on the left equals the right

But the left does not equal the right.

Let x = 1, and you'll see the two sides don't equate.
 

Gibson486

Lifer
Aug 9, 2000
18,378
2
0
Originally posted by: chuckywang
Originally posted by: BullyCanadian
Here is the question. I am gonna go get some help tomorrow, but was wondering if anyone can help me out right now (I know most of you guys are really smart)

Here is question 1
The question is to show that the equation on the left equals the right

But the left does not equal the right.

Let x = 1, and you'll see the two sides don't equate.


indeed, 1 != root(2/3)
 

BullyCanadian

Platinum Member
May 4, 2003
2,026
0
71
Originally posted by: Gibson486
Originally posted by: chuckywang
Originally posted by: BullyCanadian
Here is the question. I am gonna go get some help tomorrow, but was wondering if anyone can help me out right now (I know most of you guys are really smart)

Here is question 1
The question is to show that the equation on the left equals the right

But the left does not equal the right.

Let x = 1, and you'll see the two sides don't equate.


indeed, 1 != root(2/3)

My mistake! I wrote it wrong! missed sin before arccot
 

chuckywang

Lifer
Jan 12, 2004
20,133
1
0
Originally posted by: BullyCanadian

EDIT - There is a mistake in the question it should be cos{arctan[sin(arcot x)]} = ....

Do this problem in two parts:

First, compute y=sin(arccot x) = 1/sqrt(x^2 + 1)

Then, compute cos(arctan y) = 1/sqrt(y^2 + 1)

Plug in y= 1/sqrt(x^2 + 1) to 1/sqrt(y^2 + 1)
and you get 1/sqrt(1/(x^2+1) + 1) = sqrt(x^2 + 1)/sqrt(x^2 + 2).
 

chuckywang

Lifer
Jan 12, 2004
20,133
1
0
Originally posted by: Gibson486
Originally posted by: chuckywang
Originally posted by: BullyCanadian
Here is the question. I am gonna go get some help tomorrow, but was wondering if anyone can help me out right now (I know most of you guys are really smart)

Here is question 1
The question is to show that the equation on the left equals the right

But the left does not equal the right.

Let x = 1, and you'll see the two sides don't equate.


indeed, 1 != root(2/3)


More like 1/sqrt( (pi/4)^2 + 1) != sqrt(2/3) :)
 

BullyCanadian

Platinum Member
May 4, 2003
2,026
0
71
Originally posted by: chuckywang
Originally posted by: BullyCanadian

EDIT - There is a mistake in the question it should be cos{arctan[sin(arcot x)]} = ....

Do this problem in two parts:

First, compute y=sin(arccot x) = 1/sqrt(x^2 + 1)

Then, compute cos(arctan y) = 1/sqrt(y^2 + 1)

Plug in y= 1/sqrt(x^2 + 1) to 1/sqrt(y^2 + 1)
and you get 1/sqrt(1/(x^2+1) + 1) = sqrt(x^2 + 1)/sqrt(x^2 + 2).

ok I get everything up to this:

and you get 1/sqrt(1/(x^2+1) + 1) = sqrt(x^2 + 1)/sqrt(x^2 + 2)

how does /sqrt(1/(x^2+1) + 1) = sqrt(x^2 + 1)/sqrt(x^2 + 2)???
 

chuckywang

Lifer
Jan 12, 2004
20,133
1
0
Originally posted by: BullyCanadian
Originally posted by: chuckywang
Originally posted by: BullyCanadian

EDIT - There is a mistake in the question it should be cos{arctan[sin(arcot x)]} = ....

Do this problem in two parts:

First, compute y=sin(arccot x) = 1/sqrt(x^2 + 1)

Then, compute cos(arctan y) = 1/sqrt(y^2 + 1)

Plug in y= 1/sqrt(x^2 + 1) to 1/sqrt(y^2 + 1)
and you get 1/sqrt(1/(x^2+1) + 1) = sqrt(x^2 + 1)/sqrt(x^2 + 2).

ok I get everything up to this:

and you get 1/sqrt(1/(x^2+1) + 1) = sqrt(x^2 + 1)/sqrt(x^2 + 2)

how does /sqrt(1/(x^2+1) + 1) = sqrt(x^2 + 1)/sqrt(x^2 + 2)???


1/sqrt(1/(x^2+1) + 1) = sqrt(1/(1/(x^2+1)+1) = sqrt( (x^2+1)/(1+x^2+1)) = sqrt((x^2+1)/(x^2+2)