Sine, Cosine & Tangent Help

Subject Areas

Tools / Misc

bCalc

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scrnGC2: Calc Input

scrnGC3: f(x) Plot Input

scrnGC4: g(x) Plot Input

The inputs above will be hidden when the program finally gets launched. Currently, I am not hiding them even when you close the calculator. The purpose of the inputs is to help in debugging. This allows you to enter simple code on the calculator screen but the program translates the input to javascript math. Give it a try and see if you notice any obvious problems or have suggestions for improvements.

gCalc

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Select precision* of answer:

Select angle mode:

Enter expression to evaluate here:

The answer is shown below:

Enter function to be plotted:

f(x) =

Enter 2nd function, if needed:

g(x) =

Change or reset the x-y scaling below:

x_min =

x_max =

y_min =

y_max =

Accuracy Disclaimer

The javascript math object methods used for this calculator are not accurate for very large or very small numbers. In particular, the trigonometric functions may yield very small answers that should actually be zero or very large answers that should be infinite. This typically occurs at 90° or pi/2 intervals.

DO NOT USE WHERE HIGH PRECISION IS REQUIRED. USE AT YOUR OWN RISK.

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Sine, Cosine & Tangent Help

SOH - CAH - TOA

The three basic trig functions shown in the diagram below can be used to solve any right triangle if you are given two sides or one side and one of the acute angles.

Since the sum of the interior angles is 180°, if you are given one of the angles of a right triangle, you can always find the third angle by subtracting the known angle from 90°.

Note that Sin(A)= Cos(B), Cos(A)= Sin(B) and the Tan(A) is the reciprocal of Tan(B). This is true because the side opposite ∠ A is adjacent to ∠ B and the side adjacent ∠ A is opposite to ∠ B.

If any of the trig ratios are known, the related angle can be found using inverse trig functions; eg. ∠ A = Sin^-1(BC/AB) = Cos^-1(AC/AB) = Tan^-1(BC/AC) in the figure above.