3 ms·

I would need paper for all but the first, and could not solve the 4th without a calculator. Not sure what the norm is, here's my data point.

• T-hawk 15y ago
  pi/3 is 60°, and the sine of that is √3 / 2. But yes, that's not something one calculates by head, that's memorization. And working out √3 / 2 into decimals also takes a calculator, though I can approximate by knowing the first two significant digits would be 1.7 / 2 = 0.85. One can memorize trig tables like multiplication tables, and I do find that useful from time to time. I remember sin, cos, and tan for 0°, 30°, 45°, 60°, and 90°, and how to flip the signs to get all four quadrants from 0° to 360°.
• TheCapn 15y ago
  More of a curious question but are you saying you're incapable of solving the last one without paper or just that its really not worth the time. Any of those example questions I could do without paper (I'm 23 for a reference) but I certainly wouldn't attempt the last one without it unless someone was challenging me since it'd take more time than what its worth.
  • Someone 15y ago
    With the problem in front of me, I would not think doing the last one on paper would speed up things. On paper, it would feel like Load X Triple Store Temp Load Temp Load Y Add I would optimize that store/load away. If, on the other hand, someone told me the problem, I probably would not remember Y by the time I needed it (seven plus or minus two is about two, apparently)