Question

If A=B=45.verify that. Cos(A-B)=cosA cosB +sinA sinB

Answer 1

Answer:

Given A = 45° , B = 45°

LHS = cos(A-B)

= cos (45° - 45°)

= cos 0°

= 1

$RHS = cosAcosB+sinAsinB\\=cos45cos45+sin45sin45\\=cos^{2}45+sin^{2}45\\=1$

/* By Trigonometric identity:

cos²A+sin²A = 1 */

LHS = RHS

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Answer 2

Answer:

Step-by-step explanation: