## anonymous one year ago ???

1. IrishBoy123

by linear approximation, do you mean $$V = \frac{4}{3} \pi r^3$$, $$\Delta V = \frac{dV}{dr}\Delta r$$ ?

2. anonymous

Would I derive the first one?

3. welshfella

yes differentiate (4/3) pi r^3 which is the formula for the volume of the sphere

4. anonymous

4pir^2

5. welshfella

correct

6. anonymous

And then what

7. IrishBoy123
8. welshfella

you know the value of r and delta r - Just plug them in and calculate

9. anonymous

36pi

10. anonymous

?????

11. IrishBoy123

correct to within 0.01 inch in maths speak is: $$\Delta r = \pm 0.01$$ you got $$\frac{dV}{dr} = 4 \pi r^2$$ yourself, so finish the job

12. welshfella

36pi is correct for the value of 4 pi r^2 now you plug is the +/- 0.01

13. welshfella

* plug in

14. anonymous

.36

15. welshfella

no

16. anonymous

.036