Question

f
Cos
$cos {}^{2} 67 - sin {}^{2} 23$
Find answers

Answer 1

Cos²67° -sin²23°

Cos²67° - sin²(90-67)

Cos²67 -cos²67

= 0



I hope this will help you


-by ABHAY

Answer 2

♧♧HERE IS YOUR ANSWER♧♧



Trigonometry is the study of angles and its ratios. This study prescribes the relation amongst the sides of a triangle and angles of the triangle.



There are sine, cosine, tangent, cot, sectant and cosec ratios to an angle of a triangle.



Let me tell you an interesting fact about Trigonometry.



"Triangle" > "Trigonometry"



Remember some formulae now :



sin²θ + cos²θ = 1



sec²θ - tan²θ = 1



cosec²θ - cot²θ = 1



Want to learn more!



Here it is :



sin(A + B) = sinA cosB + cosA sinB



sin(A - B) = sinA cosB - cosA sinB



cos(A + B) = cosA cosB - sinA sinB



cos(A - B) = cosA cosB + sinA sinB


SOLUTION :

Now, sin23°
= sin(90-67)°, since sin(90-θ) = cosθ
= cos67°

So,
cos²67 - sin²23
= cos²67 - cos²67
= 0

♧♧HOPE IT HELPS YOU♧♧