webwork 10.9

Hi Dr Taylor,

I'm stuck on calculating the speed in this problem from 10.9 homework, I feel like I am close but not quite there. I'm unsure what I am doing wrong will appreciate any help.

Thank you

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OK, you're going to need to compute the root sum of squares of the components of v; it looks like instead you've used the components of a., or maybe you forgot the t multiplying the trig functions.  The right answer should be made from

 √((7sin(t)+7tcos(t))^2+(7cos(t)-7tsin(t))^2+14^2t^2)

which you can and should simplify considerably, but you need at least another t^2 in there somewhere.