Formula in 2002

  • Thread starter Thread starter leonperrins
  • Start date Start date
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leonperrins

Can any one help me with inputting the following cosine formula.

a(squared) = b(squared) + c(squared) - 2bc CosA

I want to input various values for sides a & b and angle A.
 
Hi,
To solve for different unknowns, you need to make the unknown the subject of
the formula.
eg, to solve for a:
a=square root(b(squared)+c(squared)-2bc*CosA)
as an XL formula:
=(b^2+c^2-2*b*c*COS(A))^0.5
To make it easier to input values, assign cells to contain the values.
EG.
A1 has a
B1 has b
C1 has c
D1 has A
Then the formula would look like this:
=(B1^2+C1^2-2*B1*C1*COS(D1))^0.5
It's a bit longer, but you don't have to change it each time.
Hope this helps.
Regards - Dave.
 
Can any one help me with inputting the following cosine formula.

a(squared) = b(squared) + c(squared) - 2bc CosA

I want to input various values for sides a & b and angle A.
Click to expand...

Assuming column A for a, column B for b and column D for angle A in
degrees, then in column C...

=SQRT(POWER(A1,2)+POWER(B1,2)-PRODUCT(2,A1,B1,COS(RADIANS(D1))))

Ken Johnson
 
Thanks Guys,

Unfortunately both formulae give an error when entered into Excel.

I have assumed that a "SUM" is required at the start of the formula, is this
correct?

If not please show all details for an ageing, forgetful old mathematician.
 
Thanks Guys,

Unfortunately both formulae give an error when entered into Excel.

I have assumed that a "SUM" is required at the start of the formula, is this
correct?

If not please show all details for an ageing, forgetful old mathematician.
Click to expand...

I don't get an error.
Where on the sheet are you entering your a, b and angle A values?
What is the error?
You can use SUM, but not at the start, but it's just not necessary to
use...

=SQRT(SUM(POWER(A1,2),POWER(B1,2),-PRODUCT(2,A1,B1,COS(RADIANS(D1)))))

Ken Johnson
 
Thanks Ken,
The modified formula works.

Ken Johnson said:
I don't get an error.
Where on the sheet are you entering your a, b and angle A values?
What is the error?
You can use SUM, but not at the start, but it's just not necessary to
use...

=SQRT(SUM(POWER(A1,2),POWER(B1,2),-PRODUCT(2,A1,B1,COS(RADIANS(D1)))))

Ken Johnson
Click to expand...
 
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