[Bugsy]

Hey guys I'm just going through the uploaded question. I've managed part A, but on part B I'm unsure of what the question is asking. So far I have differentiated the function y and tried to work out the gradient when x has a value of pi/4 but I'm getting a weird decimal answer I think the question is asking me to work out the equation of the tangent to the curve and then sub in the values of when x=0 to work out the y intercept? Is this correct, and if not what am I doing wrong Thanks!

[TheJ0ker]

(Original post by Bugsy)
Hey guys I'm just going through the uploaded question. I've managed part A, but on part B I'm unsure of what the question is asking. So far I have differentiated the function y and tried to work out the gradient when x has a value of pi/4 but I'm getting a weird decimal answer I think the question is asking me to work out the equation of the tangent to the curve and then sub in the values of when x=0 to work out the y intercept? Is this correct, and if not what am I doing wrong Thanks!

Yes that is what it is asking, what have you got for the equation of the tangent?

[raheem94]

(Original post by Bugsy)
Hey guys I'm just going through the uploaded question. I've managed part A, but on part B I'm unsure of what the question is asking. So far I have differentiated the function y and tried to work out the gradient when x has a value of pi/4 but I'm getting a weird decimal answer I think the question is asking me to work out the equation of the tangent to the curve and then sub in the values of when x=0 to work out the y intercept? Is this correct, and if not what am I doing wrong Thanks!

Find the equation of the tangent at

Then sub in x=0 to get the answer.

[Bugsy]

(Original post by TheJ0ker)
Yes that is what it is asking, what have you got for the equation of the tangent?

I haven't managed to get an equation for the tangent yet, because I can't work out a value for m I tried to sub in pi/4 into my dy/dx but like I said I get a long decimal which I don't think is correct.. Once I get a M value I can use the y-y1=m(x-x1) to find the equation for the tangent..

(Original post by raheem94)
Find the equation of the tangent at

Then sub in x=0 to get the answer.

Yeah this is what I'm having problems with.. For my dy/dx I got 2x.Sec^2 x + 2tanx

[TheJ0ker]

(Original post by Bugsy)
I haven't managed to get an equation for the tangent yet, because I can't work out a value for m I tried to sub in pi/4 into my dy/dx but like I said I get a long decimal which I don't think is correct.. Once I get a M value I can use the y-y1=m(x-x1) to find the equation for the tangent..



Yeah this is what I'm having problems with.. For my dy/dx I got 2x.Sec^2 x + 2tanx

Don't just plug the numbers into a calculator then. If you do it using your grey matter you will get a simple gradient involving an integer and pi.

[raheem94]

(Original post by Bugsy)
Yeah this is what I'm having problems with.. For my dy/dx I got 2x.Sec^2 x + 2tanx

Sub in



It is an exact value.

[Bugsy]

(Original post by TheJ0ker)
Don't just plug the numbers into a calculator then. If you do it using your grey matter you will get a simple gradient involving an integer and pi.

(Original post by raheem94)
Sub in



It is an exact value.

Ah okay, great I get the answer now! Sorry for being so silly, I should have tried to do it without a calculator to get an exact value.. Thanks for your help