(In reply to
computer solution by Charlie)
In degree mode the graph of the difference between left side and right side is different in form as the square term means you can't just convert the answer in radians to degrees.
A portion of the output using degrees is:
...
12.925721582095 1.16218146217761E12
12.925721582096 7.05407954271209E13
12.925721582097 2.48190357154954E13
12.925721582098 2.08111305965986E13
12.925721582099 6.64884813872391E13
...
and the answer is between 12.925721582097 and 12.925721582098 degrees.
pi = Atn(1) * 4
dr = pi / 180
...
For x = 12.925721582 To 12.9257215821 Step 0.000000000001
y = sind(x)  sind(x * x)
Text1.Text = Text1.Text & x & " " & Str(y) & crlf
DoEvents
Next
. . .
Function sind(x)
sind = Sin(x * dr)
End Function

Posted by Charlie
on 20181115 11:35:32 