2017年11月17日 · 45∘ is a special angle, along with 30∘, 60∘, 90∘, 180∘, 270∘, 360∘. tan(45∘) = 1 sin(45∘) = √2 2 cos(45∘) = √2 2 Here are some other special angles :)

2015年9月12日 · Consider the idea that a triangle will always have an angle sum of 180o. You may have seen that trigonometric functions are used directly on a triangles only when you have a right triangle. As in, when you "take the cosine" of an angle and do nothing else, the angle must be in a right triangle. When you have that, you have: 180o −90o − 45o = 45o Which means …

The exact value of cos (45°) is √ (2) / 2. If an angle in a right triangle has measure α, then the cosine of that angle, or...

How do you find the exact value of cos 45 using the sum and difference, double angle or half angle formulas?

2015年9月14日 · It is cos(225) = cos(180 +45) = cos180 ⋅ cos45− sin180 ⋅ sin45 = − 1 ⋅ √2 2 − 0 ⋅ √2 2 = − √2 2

2018年4月6日 · sin 45^@ Given: cos 45^@ From the trigonometry cofunction identities: cos theta = sin (90^@ - theta) Let theta = 45^@: " " cos 45^@ = sin (90^@ - 45^@) = sin 45^@

2015年5月10日 · Cos 135° is an angle in the second quadrant. In the second quadrant, cos is negative. cosθ = x r cos135 = cos(180 − 45) = −cos45° An angle of 45° is found in a right-angled triangle of sides 1:1:√2 cos45° = 1 √2 ∴ cos135° = −cos45° = − 1 √2 Note that √2 is an irrational number and cannot be given as an exact decimal.

2018年5月10日 · 0 Yes, it simplifies to give you zero. Now to make our lives easier, it would be better to turn the equation to: cos(45+a)cos(45-a) = sin(45-a)sin(45+a) This way we can resolve both sides without things getting mixed and muddled together. You should be comfortable with your trigonometric identities so by looking at this equation you are able to tell the four identities …

2015年8月14日 · How do you find the exact functional value sin (60˚+45˚) using the cosine sum or difference identity?

2015年8月27日 · How do you find the exact functional value cos 75 using the cosine sum or difference identity?