3 ms·
I think learning sin/cos/tan before learning that they are based on a circle is ridiculous as well. I had an epiphany when I learned that.
by ericmoritz 15y ago
I think learning sin/cos/tan before learning that they are based on a circle is ridiculous as well. I had an epiphany when I learned that.
- giardini 15y agoAfter concluding plane geometry we took trigonometry. The teacher had chosen an ugly pink-and-black text from New York State. No less than 3 inches thick, it was chock full of trigonometric formulae for us to memorize. But on day 1 she put the following on the blackboard: Indian Chief SOHCATOA: S=O/H C=A/H T=O/A where S, C, T, O, A, H are respectively, sin, cos, tangent, opposite, adjacent, and hypotenuse. The mnemonic stuck immediately. Surprised, I asked if all the formulae in the 3-inch text were in terms of those formulae, to which she replied affirmatively. I immediately realized there was little need to study trig whatsoever, since any of the complex formulas could be reduced to ratios using the SOCAHTOA principle. I barely cracked the text that semester. She disapproved somewhat of my methods but accepted them. My classmates wasted hours memorizing formulas.
- gjm11 15y agoI've no idea what was in your ugly pink and black textbook, but I'd have thought those trigonometric formulae would include lots of things like cos(A+B) = cos(A)cos(B) - sin(A)sin(B). How do you "reduce that to a ratio using the SOHCAHTOA principle"? By drawing a diagram with two right-angled triangles stuck together and doing the relevant fiddly geometry? That seems like vastly more trouble than remembering the formula. (It took me a minute to work out how to derive the formula at all that way, and I'm a pro.)