Please explain me the the confusion about the marked step...
why  a+bcoso=Rcos0(theta)  at the same time bsin0(theta)= Rsin0(theta)
what is the logic for the cosideration...
 
 
 

Asked by nitishkrnehu09 | 9th Oct, 2017, 07:26: PM

Expert Answer:

  1. This type of substitutions is done for simplification in solving.
  2. Step 15 being converted into a standard form of trigonometric formula " sinAcosB + cosAsinB = sin(A+B) "
  3. Here " sinA = sinωt " and " cosB = cosωt "
  4. but there is no simplied term for sinB and cosA. "R" is taken into consideration for the resultant amplitude from "a" and "b" 
  5. Hence, in step 16 there is substitution for " a+bcosΦ = Rcosθ " for sinA and " bsinΦ = Rsinθ " for cosB making the right hand side of step 15 in the form of sinAcosB + cosAsinB

Answered by Abhijeet Mishra | 8th Dec, 2017, 06:11: PM