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puteri [66]
4 years ago
7

What is the proof the formula for cos(A+B)=cosAcosB-sinAsinB?

Mathematics
1 answer:
brilliants [131]4 years ago
8 0
Given data, cos(A - B) = cosAcosB + sinAsinB 
<span>let, A=60' and B=30' ( here the ' sign bears degree) </span>
<span>L.H.S = cos(A - B) </span>
<span>=cos (60'-30) ( using value of A and B ) </span>
<span>=cos30' </span>
<span>= sqrt3/2 </span>
<span>R.H.S= cosAcosB + sinAsinB </span>
<span>=cos60' cos30' + sin60' sin30' </span>
<span>= 1/2* sqrt3/2+ sqrt3/2*1/2 </span>
<span>= sqrt3/4 + sqrt3/4 </span>
<span>=2 sqrt3/4 </span>
<span>= sqrt3/2 </span>
<span>so L.H.S =R.H.S or cos(A - B) = cosAcosB + sinAsinB</span>
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Step-by-step explanation:

Using your cursor/mouse, you will first choose the color black. Then you will plot the points given to you (2,2) and (5,8) by first finding the x-coordinate of (x,y). Start at 2 on the x-axis. Follow the grid line up two units so you will also be at the 2 on the y-axis. Plot or draw a dot/circle on this grid line. Go back to the x-axis and start again at 5 on the x-axis. Follow the grid line up eight units so you will also be at the 8 on the y-axis. Plot or draw a dot/circle on this grid line. Connect the dots for your line.

Using your cursor/mouse, you will choose the color blue. Then you will plot the point given to you (10,5) by first finding the x-coordinate of (x,y). Start at 10 on the x-axis. Follow the grid line up five units so you will also be at the 5 on the y-axis. Plot or draw a dot/circle on this grid line. Instead of plotting another point. This time you will count from the blue point up three units and over to the right one. Mark this grid line as a point. Now connect them.

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Step-by-step explanation:

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That's true even when you don't have any exponents.

5\times5=5^1\times5^1=5^{1+1}=5^2=25

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A negative exponent isn't fully simplified, so there's another rule to use:

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Step-by-step explanation:

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b) The girls in the class are 4 and the total number of pupils in class are 7. So, the fraction is correct✅.

c) The number of boys in class is 3✅ which is given in the ratio. Not 6❌

d) If you add the both numbers in the ratio, you will get the total number of pupils which is 7✅not 12❌

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