This is correct if the 90 is in radians. If it is in degrees then tan(90°) is infinite.
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There is also a second quadrant angle, namely, 3π/4
This graph might help:
Further: \((-1)^{1/4} \rightarrow e^{i\pi/4}\rightarrow \frac{\sqrt2}{2}(1+i)\)
You've not got it quite right! You need to take the limit as n tends to infinity to get the exponential function:
Yes, the exact result gives f(2) = 4e - 3 ≈ 7.8, as illustrated in my graph.
Euler's approximate numerical method lags well behind the exact function.
"The odometer in my car is currently 84095. It advances by ones. The tripometer is at 8018.6. It advances by tenths.
When will the numbers look "the same"? For example 84523 and 8452.3
And what is the algorithm to solve this?"
You are right not to be keen on Euler's method, especially with a step size this large - see the comparison below:
As follows:
So f(2) = y(2) = 6
I get the following:
Note that you need x2 in metres and that 6644 J = 6.644 kJ.
+33665 
