Question

From the figure the resultant R can be written as
a) R²= a² + b²+2ab cos tita
b) R²= a² + b² - 2ab cos tita
c) R²=a² + b² - 2ab sin tita d) R²= a² + b²​

Answer 1

Answer:

R^2 = A^2 +B^2 + 2ABCOSX

R^2 = A^2 +B^2 + 2AACOSX

R^2 = 2A^2 + 2A^2COSX

R^2 = 2A^2(1+COSX)

R^2 = 2A^2(2(COSX/2)^2)

( Because : {COS2X= 2(COSX)^2-1} )

R^2 = 4 A^2 (COSX/2)^2

R = 2ACOSX/2

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